52 results on '"Stefan Dongus"'
Search Results
2. Corrigendum to 'The effects of radiofrequency electromagnetic fields exposure on human self-reported symptoms: A systematic review of human experimental studies' [Environ. Int. 187 (2024) 108612]
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Xavier Bosch-Capblanch, Ekpereonne Esu, Chioma Moses Oringanje, Stefan Dongus, Hamed Jalilian, John Eyers, Christian Auer, Martin Meremikwu, and Martin Röösli
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Environmental sciences ,GE1-350 - Published
- 2024
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3. The effects of radiofrequency electromagnetic fields exposure on human self-reported symptoms: A systematic review of human experimental studies
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Xavier Bosch-Capblanch, Ekpereonne Esu, Chioma Moses Oringanje, Stefan Dongus, Hamed Jalilian, John Eyers, Christian Auer, Martin Meremikwu, and Martin Röösli
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Radiofrequency electromagnetic fields ,Idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) ,Electromagnetic hypersensitivity (EHS) ,Symptoms ,Well-being ,Sleep ,Environmental sciences ,GE1-350 - Abstract
Background: The technological applications of radiofrequency electromagnetic fields (RF-EMF) have been steadily increasing since the 1950s exposing large proportions of the population. The World Health Organization (WHO) is assessing the potential health effects of exposure to RF-EMF. Objectives: To systematically assess the effects of exposure to RF-EMF on self-reported non-specific symptoms in human subjects and to assess the accuracy of perceptions of presence or absence of RF-EMF exposure. Methods: Eligibility criteria: experimental studies carried out in the general population and in individuals with idiopathic environmental intolerance attributed to EMF (IEI-EMF), in any language.Information sources: Medline, Web of Science, PsycInfo, Cochrane Library, Epistemonikos, Embase and EMF portal, searched till April 2022.Risk of Bias (ROB): we used the RoB tool developed by OHAT adapted to the topic of this review.Synthesis of results: we synthesized studies using random effects meta-analysis and sensitivity analyses, where appropriate. Results: Included studies: 41 studies were included, mostly cross over trials and from Europe, with a total of 2,874 participants.Synthesis of results: considering the primary outcomes, we carried out meta-analyses of 10 exposure-outcomes pairs. All evidence suggested no or small non-significant effects of exposure on symptoms with high (three comparisons), moderate (four comparisons), low (one comparison) and very low (two comparisons) certainty of evidence. The effects (standard mean difference, where positive values indicate presence of symptom being exposed) in the general population for head exposure were (95% confidence intervals) 0.08 (−0.07 to 0.22) for headache, −0.01 (−0.22 to 0.20) for sleeping disturbances and 0.13 (−0.51 to 0.76) for composite symptoms; and for whole-body exposure: 0.09 (−0.35 to 0.54), 0.00 (−0.15 to 0.15) for sleeping disturbances and −0.05 (−0.17 to 0.07) for composite symptoms. For IEI-EMF individuals SMD ranged from −0.19 to 0.11, all of them with confidence intervals crossing the value of zero.Further, the available evidence suggested that study volunteers could not perceive the EMF exposure status better than what is expected by chance and that IEI-EMF individuals could not determine EMF conditions better than the general population. Discussion: Limitations of evidence: experimental conditions are substantially different from real-life situations in the duration, frequency, distance and position of the exposure. Most studies were conducted in young, healthy volunteers, who might be more resilient to RF-EMF than the general population. The outcomes of interest in this systematic review were symptoms, which are self-reported. The available information did not allow to assess the potential effects of exposures beyond acute exposure and in elderly or in chronically ill people. It cannot be ruled out that a real EMF effect in IEI-EMF groups is masked by a mix with insensitive subjects. However, studies on symptoms reporting and/or field perceptions did not find any evidence that there were particularly vulnerable individuals in the IEI-EMF group, although in open provocation studies, when volunteers were informed about the presence or absence of EMF exposure, such differences were consistently observed.Interpretation: available evidence suggests that acute RF-EMF below regulatory limits does not cause symptoms and corresponding claims in the everyday life are related to perceived and not to real EMF exposure status.
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- 2024
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4. The effects of radiofrequency electromagnetic fields exposure on tinnitus, migraine and non-specific symptoms in the general and working population: A systematic review and meta-analysis on human observational studies
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Martin Röösli, Stefan Dongus, Hamed Jalilian, John Eyers, Ekpereonne Esu, Chioma Moses Oringanje, Martin Meremikwu, and Xavier Bosch-Capblanch
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Environmental sciences ,GE1-350 - Abstract
Background: Applications emitting radiofrequency electromagnetic fields (RF-EMF; 100 kHz to 300 GHz) are widely used for communication (e.g. mobile phones), in medicine (diathermy) and in industry (RF heaters). Objectives: The objective is to systematically review the effects of longer-term or repeated local and whole human body radiofrequency electromagnetic field (RF-EMF) exposure on the occurrence of symptoms. Primary hypotheses were tinnitus, migraine and headaches in relation to RF-EMF exposure of the brain, sleep disturbances and composite symptom scores in relation to whole-body RF-EMF exposure. Methods: Eligibility criteria: We included case-control and prospective cohort studies in the general population or workers estimating local or whole-body RF-EMF exposure for at least one week.Information sources: We conducted a systematic literature search in various databases including Web of Science and Medline.Risk of bias: We used the Risk of Bias (RoB) tool developed by OHAT adapted to the topic of this review.Synthesis of results: We synthesized studies using random effects meta-analysis. Results: Included studies: We included 13 papers from eight distinct cohort and one case-control studies with a total of 486,558 participants conducted exclusively in Europe. Tinnitus is addressed in three papers, migraine in one, headaches in six, sleep disturbances in five, and composite symptom scores in five papers. Only one study addressed occupational exposure.Synthesis of results: For all five priority hypotheses, available research suggests that RF-EMF exposure below guideline values does not cause symptoms, but the evidence is very uncertain. The very low certainty evidence is due the low number of studies, possible risk of bias in some studies, inconsistencies, indirectness, and imprecision. In terms of non-priority hypotheses numerous exposure-outcome combinations were addressed in the 13 eligible papers without indication for an association related to a specific symptom or exposure source. Discussion: Limitations of evidence: This review topic includes various challenges related to confounding control and exposure assessment. Many of these aspects are inherently present and not easy to be solved in future research. Since near-field exposure from wireless communication devices is related to lifestyle, a particular challenge is to differentiate between potential biophysical effects and other potential effects from extensive use of wireless communication devices that may compete with healthy behaviour such as sleeping or physical activity. Future research needs novel and innovative methods to differentiate between these two hypothetical mechanisms.Interpretation: This is currently the best available evidence to underpin safety of RF-EMF. There is no indication that RF-EMF below guideline values causes symptoms. However, inherent limitations of the research results in substantial uncertainty. Other: Funding: This review was partially funded by the WHO radioprotection programme.Registration: The protocol for this review has been registered in Prospero (reg no CRD42021239432) and published in Environment International (Röösli et al., 2021)
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- 2024
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5. The effects of radiofrequency electromagnetic fields exposure on human self-reported symptoms: A protocol for a systematic review of human experimental studies
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Xavier Bosch-Capblanch, Ekpereonne Esu, Stefan Dongus, Chioma Moses Oringanje, Hamed Jalilian, John Eyers, Gunnhild Oftedal, Martin Meremikwu, and Martin Röösli
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Radiofrequency electromagnetic fields ,Electromagnetic hypersensitivity (EHS) ,Idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) ,Symptoms ,Well-being ,Sleep ,Environmental sciences ,GE1-350 - Abstract
Background: The technological applications of radiofrequency electromagnetic fields (RF-EMF) have been steadily increasing since the 1950s across multiple sectors exposing large proportions of the population. This fact has raised concerns related to the potential consequences to people’s health. The World Health Organization (WHO) is assessing the potential health effects of exposure to RF-EMF and has carried out an international survey amongst experts, who have identified six priority topics to be further addressed through systematic reviews, whereof the effects on symptoms is one of them. We report here the systematic review protocol of experimental studies in humans assessing the effects of RF-EMF on symptoms. Objective: Our objectives are to assess the effects of exposure to electromagnetic fields (compared to no or lower exposure levels) on symptoms in human subjects. We will also assess the accuracy of perception of presence of exposure in volunteers with and without idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF). Eligibility criteria: We will search relevant literature sources (e.g. the Web of Science, Medline, Embase, Epistemonikos) for randomized trials (comparing at least two arms) and randomised crossover trials of RF-EMF exposure that have assessed the effects on symptoms. We will also include studies that have measured the accuracy of the perception of the presence or absence of exposure. We will include studies in any language. Study appraisal and synthesis: Studies will be assessed against inclusion criteria by two independent reviewers. Data on study characteristics, participants, exposure, comparators and effects will be extracted using a specific template for this review, by two independent reviewers. Discrepancies will be solved by consensus. Risk of bias (ROB) will be assessed using the ROB Rating Tool for Human and Animal Studies and the level of confidence in the evidence of the exposure-outcome relations will be assessed using the GRADE approach. For the perception studies, we will use adapted versions of the ROB tool and GRADE assessment. Where appropriate, data will be combined using meta-analytical techniques.
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- 2022
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6. The effects of radiofrequency electromagnetic fields exposure on tinnitus, migraine and non-specific symptoms in the general and working population: A protocol for a systematic review on human observational studies
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Martin Röösli, Stefan Dongus, Hamed Jalilian, Maria Feychting, John Eyers, Ekpereonne Esu, Chioma Moses Oringanje, Martin Meremikwu, and Xavier Bosch-Capblanch
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Microwave ,Non-specific symptoms ,Sleep ,Headache ,Tinnitus ,Migraine ,Environmental sciences ,GE1-350 - Abstract
Background: Applications emitting radiofrequency electromagnetic fields (RF-EMF; 100 kHz to 300 GHz) are widely used for communication (e.g. mobile phones), in medicine (diathermy) and in industry (RF heaters). Concern has been raised that RF-EMF exposure affects health related quality of life, because a part of the population reports to experience a variety of symptoms related to low exposure levels below regulatory limits. Objectives: To systematically review the effects of longer-term or repeated local and whole human body RF-EMF exposure on the occurrence of symptoms evaluating migraine, tinnitus, headaches, sleep disturbances and composite symptom scores as primary outcomes. Methods: We will follow the WHO handbook for guideline development. For the development of the systematic review protocol we considered handbook for conducting systematic reviews for health effects evaluations from the National Toxicology Program-Office of Health Assessment and Translation (NTP-OHAT) and COSTER (Recommendations for the conduct of systematic reviews in toxicology and environmental health research). Eligibility criteria: Peer-reviewed epidemiological studies in the general population or workers aiming to investigate the association between local or whole-body RF-EMF exposure for at least one week and symptoms are eligible for inclusion. Only cohort, case-control and panel studies will be included. Information sources: We will search the scientific literature databases Medline, Web of Science, PsycInfo, Cochrane Library, Epistemonikos and Embase, using a predefined search strategy. This search will be supplemented by a search in the EMF-Portal and checks of reference lists of relevant papers and reviews. Study appraisal and synthesis method: Data from included papers will be extracted according to predefined forms. Findings will be summarized in tables, graphical displays and in a narrative synthesis of the available evidence, complemented with meta-analyses. We will separately review effects of local, far field and occupational exposure. Risk of bias: The internal validity of included studies will be assessed using the NTP-OHAT Risk of Bias Rating Tool for Human and Animal Studies, elaborated to observational RF-EMF studies. Evidence appraisal: To rate certainty of the evidence, we will use the OHAT GRADE-based approach for epidemiological studies. Framework and funding: This protocol concerns one of the ten different systematic reviews considered in a larger systematic review of the World Health Organization to assess potential health effects of exposure to RF-EMF in the general and working population. Registration: PROSPERO CRD42021239432.
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- 2021
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7. Exposure to radiofrequency electromagnetic fields: Comparison of exposimeters with a novel body-worn distributed meter
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Anke Huss, Stefan Dongus, Reza Aminzadeh, Arno Thielens, Matthias van den Bossche, Patrick Van Torre, René de Seze, Elisabeth Cardis, Marloes Eeftens, Wout Joseph, Roel Vermeulen, and Martin Röösli
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Measurements ,RF-EMF ,ExpoM-RF ,EME SPY ,Comparison exposimeters ,Microenvironments ,Environmental sciences ,GE1-350 - Abstract
Background: Exposure to radiofrequency electromagnetic fields (RF-EMF) is often measured with personal exposimeters, but the accuracy of measurements can be hampered as carrying the devices on-body may result in body shielding. Further, the compact design may compromise the frequency selectivity of the sensor. The aim of this study was to compare measurements obtained using a multi-band body-worn distributed-exposimeter (BWDM) with two commercially available personal exposimeters (ExpoM-RF and EmeSpy 200) under real-life conditions. Methods: The BWDM measured power density in 10 frequency bands (800, 900, 1800, 2100, 2600 MHz, DECT 1900 MHz, WiFi 2.4 GHz; with separate uplink/downlink bands for 900, 1800 and 2100 MHz); using 20 separate antennas integrated in a vest and placed on diametrically opposite locations on the body, to minimize body-shielding. RF-EMF exposure data were collected from several microenvironments (e.g. shopping areas, train stations, outdoor rural/ urban residential environments, etc.) by walking around pre-defined areas/routes in Belgium, Spain, France, the Netherlands and Switzerland. Measurements were taken every 1–4 s with the BWDM in parallel with an ExpoM-RF and an EmeSpy 200 exposimeter. We calculated medians and interquartile ranges (IQRs) and compared difference, ratios and correlations of geometric mean RF-EMF exposure levels per microenvironment as measured with the exposimeters and the BWDM. Results: Across 267 microenvironments, medians and IQR of total BWDM measured RF-EMF exposure was 0.13 (0.05–0.33) mW/m2. Difference: IQR of exposimeters minus BWDM exposure levels was −0.011 (−0.049 to 0.0095) mW/m2 for the ExpoM-RF and −0.056 (−0.14 to −0.017) for the EmeSpy 200; ratios (exposimeter/BWDM) of total exposure had an IQR of 0.79 (0.55–1.1) for the ExpoM-RF and 0.29 (0.22–0.38) for the EmeSpy 200. Spearman correlations were 0.93 for the ExpoM-RF vs the BWDM and 0.96 for the EmeSpy 200 vs the BWDM. Discussion and conclusions: Results indicate that exposimeters worn on-body provide somewhat lower total RF-EMF exposure as compared to measurements conducted with the BWDM, in line with effects from body shielding. Ranking of exposure levels of microenvironments showed high correspondence between the different device types. Our results are informative for the interpretation of existing epidemiological research results.
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- 2021
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8. The underlying reasons for very high levels of bed net use, and higher malaria infection prevalence among bed net users than non-users in the Tanzanian city of Dar es Salaam: a qualitative study
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Daniel Msellemu, Aloysia Shemdoe, Christina Makungu, Yeromini Mlacha, Khadija Kannady, Stefan Dongus, Gerry F. Killeen, and Angel Dillip
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Arctic medicine. Tropical medicine ,RC955-962 ,Infectious and parasitic diseases ,RC109-216 - Abstract
Abstract Background Bed nets reduce malaria-related illness and deaths, by forming a protective barrier around people sleeping under them. When impregnated with long-lasting insecticide formulations they also repel or kill mosquitoes attempting to feed upon sleeping humans, and can even suppress entire populations of malaria vectors that feed predominantly upon humans. Nevertheless, an epidemiological study in 2012 demonstrated higher malaria prevalence among bed net users than non-users in urban Dar es Salaam, Tanzania. Methods Focus group discussions were conducted with women from four selected wards of Dar es Salaam city, focusing on four major themes relating to bed net use behaviours: (1) reasons for bed net use, (2) reasons for not using bed nets, (3) stimuli or reminders for people to use a bed net (4) perceived reasons for catching malaria while using a bed net. An analytical method by framework grouping of relevant themes was used address key issues of relevance to the study objectives. Codes were reviewed and grouped into categories and themes. Results All groups said the main reason for bed net use was protection against malaria. Houses with well-screened windows, with doors that shut properly, and that use insecticidal sprays against mosquitoes, were said not to use bed nets, while frequent attacks from malaria was the main stimulus for people to use bed nets. Various reasons were mentioned as potential reasons that compromise bed net efficacy, the most common of which were: (1) bed net sharing by two or more people, especially if one occupant tends to come to bed late at night, and does not tuck in the net 71%; (2) one person shares the bed but does not use the net, moving it away from the side on which s/he sleeps 68%; (3) ineffective usage habits, called ulalavi, in which a sprawling sleeper either touches the net while sleeping up against it or leaves a limb hanging outside of it 68%. Less common reasons mentioned included: (1) Small bed nets which become un-tucked at night (31%); (2) Bed nets with holes large enough to allow mosquitoes to pass (28%); and (3) Going to bed late after already being bitten outdoors (24%). Conclusions Behaviours associated with bed net use like; bed sharing, bed net non compliant-bedfellow, sleeping pattern like ulalavi and some physical bed net attributes compromise its effectiveness and supposedly increase of malaria infection to bed net users. While some well-screened houses looked to instigate low malaria prevalence to non-bed net users.
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- 2017
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9. Informing new or improved vector control tools for reducing the malaria burden in Tanzania: a qualitative exploration of perceptions of mosquitoes and methods for their control among the residents of Dar es Salaam
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Christina Makungu, Stephania Stephen, Salome Kumburu, Nicodem J. Govella, Stefan Dongus, Zoe Jane-Lara Hildon, Gerry F. Killeen, and Caroline Jones
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Mosquito ,Malaria ,Community perceptions ,Qualitative ,Photovoice ,Bed net ,Arctic medicine. Tropical medicine ,RC955-962 ,Infectious and parasitic diseases ,RC109-216 - Abstract
Abstract Background The effectiveness of malaria prevention with long-lasting insecticidal nets and indoor residual spraying is limited by emerging insecticide resistance, evasive mosquito behaviours that include outdoor biting, sub-optimal implementation and inappropriate use. New vector control interventions are required and their potential effectiveness will be enhanced if existing household perceptions and practices are integrated into intervention design. Methods This qualitative descriptive study used focus groups discussions, in-depth interviews and photovoice methods to explore mosquito control perceptions and practices among residents in four study sites in Dar es Salaam, Tanzania. Results Mosquitoes were perceived as a growing problem, directly attributed to widespread environmental deterioration and lack of effective mosquito control interventions. Malaria and nuisance biting were perceived as the main problem caused by mosquitoes. Breeding sites were clearly distinguished from resting sites but residents did not differentiate between habitats producing malaria vector mosquitoes and others producing mostly nuisance mosquitoes. The most frequently mentioned protection methods in the wealthiest locations were bed nets, aerosol insecticide sprays, window screens, and fumigation, while bed nets were most frequently mentioned and described as ‘part of the culture’ in the least wealthy locations. Mosquito-proofed housing was consistently viewed as desirable, but considered unaffordable outside wealthiest locations. Slapping and covering up with clothing were most commonly used to prevent biting outdoors. Despite their utility outdoors, topical repellents applied to the skin were considered expensive, and viewed with suspicion due to perceived side effects. Improving the local environment was the preferred method for preventing outdoor biting. Affordability, effectiveness, availability, practicality, as well as social influences, such as government recommendations, socialization and internalization (familiarization and habit) were described as key factors influencing uptake. Conclusions Outdoor transmission is widely accepted as an obstacle to malaria elimination. Larval source management, targeting both malaria vectors and nuisance-biting mosquitoes, is the preferred method for mosquito control among the residents of Dar es Salaam and should be prioritized for development alongside new methods for outdoor personal protection. Even if made available, effective and affordable, these additional interventions may require time and user experience to achieve positive reputations and trustworthiness.
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- 2017
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10. Topographic mapping of the interfaces between human and aquatic mosquito habitats to enable barrier targeting of interventions against malaria vectors
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Victoria M. Mwakalinga, Benn K. D. Sartorius, Alex J. Limwagu, Yeromin P. Mlacha, Daniel F. Msellemu, Prosper P. Chaki, Nicodem J. Govella, Maureen Coetzee, Stefan Dongus, and Gerry F. Killeen
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geophysical topography ,spatial modelling ,plasmodium falciparum ,malaria ,anopheles gambiae ,barrier-targeted interventions ,Science - Abstract
Geophysical topographic metrics of local water accumulation potential are freely available and have long been known as high-resolution predictors of where aquatic habitats for immature Anopheles mosquitoes are most abundant, resulting in elevated densities of adult malaria vectors and human infection burden. Using existing entomological and epidemiological survey data, here we illustrate how topography can also be used to map out the interfaces between wet, unoccupied valleys and dry, densely populated uplands, where malaria vector densities and infection risk are focally exacerbated. These topographically identifiable geophysical boundaries experience disproportionately high vector densities and malaria transmission risk, because this is where Anopheles mosquitoes first encounter humans when they search for blood after emerging or ovipositing in the valleys. Geophysical topographic indicators accounted for 67% of variance for vector density but for only 43% for infection prevalence, so they could enable very selective targeting of interventions against the former but not the latter (targeting ratios of 5.7 versus 1.5 to 1, respectively). So, in addition to being useful for targeting larval source management to wet valleys, geophysical topographic indicators may also be used to selectively target adult Anopheles mosquitoes with insecticidal residual sprays, fencing, vapour emanators or space sprays to barrier areas along their fringes.
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- 2018
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11. Mapping hotspots of malaria transmission from pre-existing hydrology, geology and geomorphology data in the pre-elimination context of Zanzibar, United Republic of Tanzania
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Andrew Hardy, Zawadi Mageni, Stefan Dongus, Gerry Killeen, Mark G Macklin, Silas Majambare, Abdullah Ali, Mwinyi Msellem, Abdul-Wahiyd Al-Mafazy, Mark Smith, and Chris Thomas
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Mosquito breeding habitat ,Malaria ,Larval source management ,Hydrology ,Geomorphology ,Geology ,Infectious and parasitic diseases ,RC109-216 - Abstract
Abstract Background Larval source management strategies can play an important role in malaria elimination programmes, especially for tackling outdoor biting species and for eliminating parasite and vector populations when they are most vulnerable during the dry season. Effective larval source management requires tools for identifying geographic foci of vector proliferation and malaria transmission where these efforts may be concentrated. Previous studies have relied on surface topographic wetness to indicate hydrological potential for vector breeding sites, but this is unsuitable for karst (limestone) landscapes such as Zanzibar where water flow, especially in the dry season, is subterranean and not controlled by surface topography. Methods We examine the relationship between dry and wet season spatial patterns of diagnostic positivity rates of malaria infection amongst patients reporting to health facilities on Unguja, Zanzibar, with the physical geography of the island, including land cover, elevation, slope angle, hydrology, geology and geomorphology in order to identify transmission hot spots using Boosted Regression Trees (BRT) analysis. Results The distribution of both wet and dry season malaria infection rates can be predicted using freely available static data, such as elevation and geology. Specifically, high infection rates in the central and southeast regions of the island coincide with outcrops of hard dense limestone which cause locally elevated water tables and the location of dolines (shallow depressions plugged with fine-grained material promoting the persistence of shallow water bodies). Conclusions This analysis provides a tractable tool for the identification of malaria hotspots which incorporates subterranean hydrology, which can be used to target larval source management strategies.
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- 2015
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12. Long-term trends in Anopheles gambiae insecticide resistance in Côte d’Ivoire
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Constant AV Edi, Benjamin G Koudou, Louise Bellai, Akre M Adja, Mouhamadou Chouaibou, Bassirou Bonfoh, Sarah JE Barry, Paul CD Johnson, Pie Müller, Stefan Dongus, Eliezer K N’Goran, Hilary Ranson, and David Weetman
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Malaria intervention ,Pyrethroid ,Carbamate ,Organochlorine ,Organophosphate ,Multiple resistance ,Infectious and parasitic diseases ,RC109-216 - Abstract
Abstract Background Malaria control is heavily dependent on the use of insecticides that target adult mosquito vectors via insecticide treated nets (ITNs) or indoor residual spraying (IRS). Four classes of insecticide are approved for IRS but only pyrethroids are available for ITNs. The rapid rise in insecticide resistance in African malaria vectors has raised alarms about the sustainability of existing malaria control activities. This problem might be particularly acute in Côte d’Ivoire where resistance to all four insecticide classes has recently been recorded. Here we investigate temporal trends in insecticide resistance across the ecological zones of Côte d’Ivoire to determine whether apparent pan-African patterns of increasing resistance are detectable and consistent across insecticides and areas. Methods We combined data on insecticide resistance from a literature review, and bioassays conducted on field-caught Anopheles gambiae mosquitoes for the four WHO-approved insecticide classes for ITN/IRS. The data were then mapped using Geographical Information Systems (GIS) and the IR mapper tool to provide spatial and temporal distribution data on insecticide resistance in An. gambiae sensu lato from Côte d’Ivoire between 1993 and 2014. Results Bioassay mortality decreased over time for all insecticide classes, though with significant spatiotemporal variation, such that stronger declines were observed in the southern ecological zone for DDT and pyrethroids than in the central zone, but with an apparently opposite effect for the carbamate and organophosphate. Variation in relative abundance of the molecular forms, coupled with dramatic increase in kdr 1014F frequency in M forms (An. coluzzii) seems likely to be a contributory factor to these patterns. Although records of resistance across insecticide classes have become more common, the number of classes tested in studies has also increased, precluding a conclusion that multiple resistance has also increased. Conclusion Our analyses attempted synthesis of 22 years of bioassay data from Côte d’Ivoire, and despite a number of caveats and potentially confounding variables, suggest significant but spatially-variable temporal trends in insecticide resistance. In the light of such spatio-temporal dynamics, regular, systematic and spatially-expanded monitoring is warranted to provide accurate information on insecticide resistance for control programme management.
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- 2014
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13. Fine scale mapping of malaria infection clusters by using routinely collected health facility data in urban Dar es Salaam, Tanzania
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Yeromin P. Mlacha, Prosper P. Chaki, Alpha D. Malishee, Victoria M. Mwakalinga, Nicodem J. Govella, Alex J. Limwagu, John M. Paliga, Daniel F. Msellemu, Zawadi D. Mageni, Dianne J. Terlouw, Gerry F. Killeen, and Stefan Dongus
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Malaria ,Spatial heterogeneity ,Hot spots ,GIS ,Tanzania ,Geography (General) ,G1-922 - Abstract
This study investigated whether passively collected routine health facility data can be used for mapping spatial heterogeneities in malaria transmission at the level of local government housing cluster administrative units in Dar es Salaam, Tanzania. From June 2012 to January 2013, residential locations of patients tested for malaria at a public health facility were traced based on their local leaders’ names and geo-referencing the point locations of these leaders’ houses. Geographic information systems (GIS) were used to visualise the spatial distribution of malaria infection rates. Spatial scan statistics was deployed to detect spatial clustering of high infection rates. Among 2407 patients tested for malaria, 46.6% (1121) could be traced to their 411 different residential housing clusters. One small spatially aggregated cluster of neighbourhoods with high prevalence was identified. While the home residence housing cluster leader was unambiguously identified for 73.8% (240/325) of malaria-positive patients, only 42.3% (881/2082) of those with negative test results were successfully traced. It was concluded that recording simple points of reference during routine health facility visits can be used for mapping malaria infection burden on very fine geographic scales, potentially offering a feasible approach to rational geographic targeting of malaria control interventions. However, in order to tap the full potential of this approach, it would be necessary to optimise patient tracing success and eliminate biases by blinding personnel to test results.
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- 2017
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14. A Multi-Band Body-Worn Distributed Radio-Frequency Exposure Meter: Design, On-Body Calibration and Study of Body Morphology
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Reza Aminzadeh, Arno Thielens, Sam Agneessens, Patrick Van Torre, Matthias Van den Bossche, Stefan Dongus, Marloes Eeftens, Anke Huss, Roel Vermeulen, René de Seze, Paul Mazet, Elisabeth Cardis, Hendrik Rogier, Martin Röösli, Luc Martens, and Wout Joseph
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radio frequency ,personal exposure meter ,dosimetry ,body morphology ,calibration ,measurement uncertainty ,Chemical technology ,TP1-1185 - Abstract
A multi-band Body-Worn Distributed exposure Meter (BWDM) calibrated for simultaneous measurement of the incident power density in 11 telecommunication frequency bands, is proposed. The BDWM consists of 22 textile antennas integrated in a garment and is calibrated on six human subjects in an anechoic chamber to assess its measurement uncertainty in terms of 68% confidence interval of the on-body antenna aperture. It is shown that by using multiple antennas in each frequency band, the uncertainty of the BWDM is 22 dB improved with respect to single nodes on the front and back of the torso and variations are decreased to maximum 8.8 dB. Moreover, deploying single antennas for different body morphologies results in a variation up to 9.3 dB, which is reduced to 3.6 dB using multiple antennas for six subjects with various body mass index values. The designed BWDM, has an improved uncertainty of up to 9.6 dB in comparison to commercially available personal exposure meters calibrated on body. As an application, an average incident power density in the range of 26.7–90.8 μW·m − 2 is measured in Ghent, Belgium. The measurements show that commercial personal exposure meters underestimate the actual exposure by a factor of up to 20.6.
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- 2018
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15. Urban agriculture and Anopheles habitats in Dar es Salaam, Tanzania
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Stefan Dongus, Dickson Nyika, Khadija Kannady, Deo Mtasiwa, Hassan Mshinda, Laura Gosoniu, Axel W. Drescher, Ulrike Fillinger, Marcel Tanner, Gerry F. Killeen, and Marcia C. Castro
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urban agriculture, Anopheles larvae, geographical information systems, malaria risk, malaria control, Tanzania. ,Geography (General) ,G1-922 - Abstract
A cross-sectional survey of agricultural areas, combined with routinely monitored mosquito larval information, was conducted in urban Dar es Salaam, Tanzania, to investigate how agricultural and geographical features may influence the presence of Anopheles larvae. Data were integrated into a geographical information systems framework, and predictors of the presence of Anopheles larvae in farming areas were assessed using multivariate logistic regression with independent random effects. It was found that more than 5% of the study area (total size 16.8 km2) was used for farming in backyard gardens and larger open spaces. The proportion of habitats containing Anopheles larvae was 1.7 times higher in agricultural areas compared to other areas (95% confidence interval = 1.56-1.92). Significant geographic predictors of the presence of Anopheles larvae in gardens included location in lowland areas, proximity to river, and relatively impermeable soils. Agriculture-related predictors comprised specific seedbed types, mid-sized gardens, irrigation by wells, as well as cultivation of sugar cane or leafy vegetables. Negative predictors included small garden size, irrigation by tap water, rainfed production and cultivation of leguminous crops or fruit trees. Although there was an increased chance of finding Anopheles larvae in agricultural sites, it was found that breeding sites originated by urban agriculture account for less than a fifth of all breeding sites of malaria vectors in Dar es Salaam. It is suggested that strategies comprising an integrated malaria control effort in malaria-endemic African cities include participatory involvement of farmers by planting shade trees near larval habitats.
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- 2009
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16. The effect of antenna polarization and body morphology on the measurement uncertainty of a wearable multi-band distributed exposure meter.
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Reza Aminzadeh, Arno Thielens, Sam Agneessens, Patrick Van Torre, Matthias Van den Bossche, Stefan Dongus, Marloes Eeftens, Anke Huss, Roel Vermeulen, René de Seze, Paul Mazet, Elisabeth Cardis, Hendrik Rogier, Martin Röösli, Luc Martens, and Wout Joseph
- Published
- 2019
- Full Text
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17. Gesundheitsrisiko Mobilfunkstrahlung? Was ändert sich mit 5G?
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Martin Röösli, Omar Hahad, Stefan Dongus, Nicolas Loizeau, Andreas Daiber, Thomas Münzel, and Marloes Eeftens
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General Medicine - Abstract
ZusammenfassungDie Exposition der Bevölkerung durch hochfrequente elektromagnetische Felder (HF-EMF) wird durch die körpernahe Nutzung von drahtlosen Kommunikationsgeräten dominiert. Die Exposition durch körperferne Sendeanlagen liegt im Durchschnitt mehrere Größenordnungen unterhalb der internationalen Richtwerte. Mit der zunehmenden mobilen Datennutzung und der damit verbundenen Nutzung von höheren Frequenzen für 5G ist mit einer Verdichtung des Mobilfunknetzes zu rechnen. Damit steigt aber nicht notgedrungen die HF-EMF-Gesamtexposition der Bevölkerung, da Mobiltelefone bei besserer Signalqualität weniger stark emittieren. 5G ist eine technologische Weiterentwicklung der bisherigen Mobilfunktechnologie mit gleichen biophysikalischen Eigenschaften. Bisher konnten keine gesundheitlichen Auswirkungen unterhalb der Richtwerte konsistent nachgewiesen werden. Beobachtete biologische Effekte wie beispielsweise auf die elektrische Aktivität des Gehirns oder auf das oxidative Gleichgewicht bei hoher lokaler Exposition im Bereich der Expositionsrichtwerte stellen nach heutigem Kenntnisstand kein Gesundheitsrisiko dar.
- Published
- 2021
18. Santé et environnement - Vers une approche globale
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Stefan Dongus
- Abstract
Dans un contexte d’accroissement de la vulnérabilité des êtres humains et des sociétés humaines face au dérèglement climatique et à l’effondrement de la biodiversité, il devient indispensable de mener une réflexion approfondie sur les liens complexes qu’entretiennent l’environnement et notre santé. Appréhender un sujet aussi multidimensionnel nécessite de s’ouvrir à différentes perspectives. En effet, si nous voulons apprendre à prendre soin et à soigner autrement, en tenant compte de ce que l’on nomme «l’interdépendance du vivant», nous devons prêter attention aux connaissances apportées par les sciences humaines et sociales, les sciences de l’environnement, les sciences de l’ingénierie ou encore les sciences de la santé. Ce livre écrit par quelque 70 autrices et auteurs d’horizons disciplinaires différents et revu indépendamment par plus de 30 expertes et experts est une invitation à aller voir au-delà de son propre champ professionnel. Il s’adresse à toutes les personnes soucieuses de trouver quelques clés de compréhension pour penser la santé dans l’environnement et entamer une nécessaire transformation socioécologique des services de santé.
- Published
- 2022
19. Antwort auf den Leserbrief 'Kritik am Artikel zu 5G: Aussagen entsprechen nicht dem Stand der Forschung'
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Martin Röösli, Omar Hahad, Stefan Dongus, Nicolas Loizeau, Andreas Daiber, Thomas Münzel, and Marloes Eeftens
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General Medicine - Published
- 2022
20. Health effects of WiFi radiation: a review based on systematicquality evaluation
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Hamed Jalilian, Martin Röösli, Stefan Dongus, and David Schürmann
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Environmental Engineering ,Risk analysis (engineering) ,business.industry ,media_common.quotation_subject ,Medicine ,Quality (business) ,business ,Risk assessment ,Pollution ,Waste Management and Disposal ,Water Science and Technology ,media_common - Abstract
Although WiFi contributes little to totalradiofrequency electromagnetic field (RF-EMF) exposure in our everyday environ-ment, concern has raised whether this spe-cific type of modulated RF-EMF causeshealth problems. The aim of this review isto evaluate all types of studies that investi-gated biological and health effects of WiFiexposure and fulfilled basic quality criteria.Eligible for inclusion were epidemiological,human experimental,in vivoandin vitrostudies using realistic WiFi exposure set-tings. We conducted a systematic literaturesearch for all papers published betweenJanuary 1997 and August 2020 followed by a quality review addressing blinding and dosimetry inexperimental studies and various types of biases in epidemiological studies. All studies fulfilling thequality criteria were descriptively summarized in terms of observation or absence of associations.From 1385 articles identified by the literature search, 23 fulfilled basic quality criteria: 6 epidemio-logical papers, 6 human experimental articles, 9in vivoarticles, and 2in vitroarticles. Whereasinvivoandin vitrostudies applied exposure levels up to 4 W/kg, human studies dealt with exposurelevels several orders of magnitude below the ICNIRP guidelines, which are typical for WiFi exposuresituations in the everyday environment. Numerous outcomes ranging from biological markers tosymptoms were mostly found not to be associated with WiFi exposure. Sporadic findings were notconsistent in terms of outcomes or exposure-response associations. This review based on a system-atic literature search and quality evaluation does not suggest detrimental health effects from WiFiexposure below regulatory limits.
- Published
- 2022
21. Letter to the Editor 'Mobile phone electromagnetic radiation and the risk of headache: a systematic review and meta‑analysis'
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Hamed Jalilian, Stefan Dongus, Xavier Bosch-Capblanch, and Martin Röösli
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Public Health, Environmental and Occupational Health - Published
- 2022
22. The effects of radiofrequency electromagnetic fields exposure on tinnitus, migraine and non-specific symptoms in the general and working population: a protocol for a systematic review on human observational studies
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Chioma Oringanje, Hamed Jalilian, Xavier Bosch-Capblanch, Maria Feychting, John Eyers, Stefan Dongus, Ekpereonne Esu, Martin M Meremikwu, and Martin Röösli
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medicine.medical_specialty ,Migraine Disorders ,Population ,MEDLINE ,PsycINFO ,Cochrane Library ,Article ,Non-specific symptoms ,Tinnitus ,Electromagnetic Fields ,medicine ,Animals ,Humans ,GE1-350 ,Internal validity ,education ,Migraine ,General Environmental Science ,Protocol (science) ,education.field_of_study ,business.industry ,Headache ,Environmental sciences ,Observational Studies as Topic ,Systematic review ,Family medicine ,Quality of Life ,Observational study ,business ,Sleep ,Microwave ,Systematic Reviews as Topic - Abstract
Highlights • There is public concern to develop non-specific symptoms from EMF. • No up to date comprehensive systematic review is available. • Priority outcomes for head exposure are tinnitus, migraine, and headaches. • Further priority outcomes are sleep disturbances and composite symptom scores., Background Applications emitting radiofrequency electromagnetic fields (RF-EMF; 100 kHz to 300 GHz) are widely used for communication (e.g. mobile phones), in medicine (diathermy) and in industry (RF heaters). Concern has been raised that RF-EMF exposure affects health related quality of life, because a part of the population reports to experience a variety of symptoms related to low exposure levels below regulatory limits. Objectives To systematically review the effects of longer-term or repeated local and whole human body RF-EMF exposure on the occurrence of symptoms evaluating migraine, tinnitus, headaches, sleep disturbances and composite symptom scores as primary outcomes. Methods We will follow the WHO handbook for guideline development. For the development of the systematic review protocol we considered handbook for conducting systematic reviews for health effects evaluations from the National Toxicology Program-Office of Health Assessment and Translation (NTP-OHAT) and COSTER (Recommendations for the conduct of systematic reviews in toxicology and environmental health research). Eligibility criteria Peer-reviewed epidemiological studies in the general population or workers aiming to investigate the association between local or whole-body RF-EMF exposure for at least one week and symptoms are eligible for inclusion. Only cohort, case-control and panel studies will be included. Information sources We will search the scientific literature databases Medline, Web of Science, PsycInfo, Cochrane Library, Epistemonikos and Embase, using a predefined search strategy. This search will be supplemented by a search in the EMF-Portal and checks of reference lists of relevant papers and reviews. Study appraisal and synthesis method Data from included papers will be extracted according to predefined forms. Findings will be summarized in tables, graphical displays and in a narrative synthesis of the available evidence, complemented with meta-analyses. We will separately review effects of local, far field and occupational exposure. Risk of bias The internal validity of included studies will be assessed using the NTP-OHAT Risk of Bias Rating Tool for Human and Animal Studies, elaborated to observational RF-EMF studies. Evidence appraisal To rate certainty of the evidence, we will use the OHAT GRADE-based approach for epidemiological studies. Framework and funding This protocol concerns one of the ten different systematic reviews considered in a larger systematic review of the World Health Organization to assess potential health effects of exposure to RF-EMF in the general and working population. Registration PROSPERO CRD42021239432.
- Published
- 2021
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23. The effects of radiofrequency electromagnetic fields exposure on human self-reported symptoms: a protocol for a systematic review of human experimental studies
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Hamed Jalilian, Chioma Oringanje, Xavier Bosch-Capblanch, Ekpereonne Esu, Martin M Meremikwu, Martin Röösli, Stefan Dongus, Gunnhild Oftedal, and John Eyers
- Subjects
Radio Waves ,media_common.quotation_subject ,Well-being ,Population ,MEDLINE ,World Health Organization ,Radiofrequency electromagnetic fields ,Article ,Idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) ,law.invention ,Electromagnetic Fields ,Randomized controlled trial ,law ,Surveys and Questionnaires ,Perception ,Animals ,Humans ,Medicine ,GE1-350 ,education ,General Environmental Science ,media_common ,Protocol (science) ,education.field_of_study ,business.industry ,Headache ,Environmental Exposure ,Idiopathic environmental intolerance ,Confidence interval ,Electromagnetic hypersensitivity (EHS) ,Environmental sciences ,Systematic review ,Symptoms ,Self Report ,Sleep ,business ,Mobile phone ,Cell Phone ,Systematic Reviews as Topic ,Clinical psychology - Abstract
Highlights • There is public concern about the potential health effects of exposure to EMF. • There is no updated synthesis of research evidence produced in experimental studies. • We are considering the effects on symptoms. • This evidence, together with evidence from other research syntheses, will inform future World Health Organization recommendations., Background The technological applications of radiofrequency electromagnetic fields (RF-EMF) have been steadily increasing since the 1950s across multiple sectors exposing large proportions of the population. This fact has raised concerns related to the potential consequences to people’s health. The World Health Organization (WHO) is assessing the potential health effects of exposure to RF-EMF and has carried out an international survey amongst experts, who have identified six priority topics to be further addressed through systematic reviews, whereof the effects on symptoms is one of them. We report here the systematic review protocol of experimental studies in humans assessing the effects of RF-EMF on symptoms. Objective Our objectives are to assess the effects of exposure to electromagnetic fields (compared to no or lower exposure levels) on symptoms in human subjects. We will also assess the accuracy of perception of presence of exposure in volunteers with and without idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF). Eligibility criteria We will search relevant literature sources (e.g. the Web of Science, Medline, Embase, Epistemonikos) for randomized trials (comparing at least two arms) and randomised crossover trials of RF-EMF exposure that have assessed the effects on symptoms. We will also include studies that have measured the accuracy of the perception of the presence or absence of exposure. We will include studies in any language. Study appraisal and synthesis Studies will be assessed against inclusion criteria by two independent reviewers. Data on study characteristics, participants, exposure, comparators and effects will be extracted using a specific template for this review, by two independent reviewers. Discrepancies will be solved by consensus. Risk of bias (ROB) will be assessed using the ROB Rating Tool for Human and Animal Studies and the level of confidence in the evidence of the exposure-outcome relations will be assessed using the GRADE approach. For the perception studies, we will use adapted versions of the ROB tool and GRADE assessment. Where appropriate, data will be combined using meta-analytical techniques.
- Published
- 2021
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24. A multi-band body-worn distributed exposure meter for personal radio-frequency dosimetry in diffuse indoor environments
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Reza Aminzadeh, Luc Martens, René de Seze, Davy P. Gaillot, Hendrik Rogier, Wout Joseph, Arno Thielens, Stefan Dongus, Marloes Eeftens, Roel Vermeulen, Lamine Kone, Patrick Van Torre, Leen Verloock, Elisabeth Cardis, Matthias Van den Bossche, Sam Agneessens, Martine Lienard, Anke Huss, Martin Röösli, Universiteit Gent = Ghent University [Belgium] (UGENT), Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Télécommunication, Interférences et Compatibilité Electromagnétique (IEMN-TELICE), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Universiteit Gent = Ghent University (UGENT), and Télécommunication, Interférences et Compatibilité Electromagnétique - IEMN (TELICE - IEMN)
- Subjects
radio-frequency ,Spectrum analyzer ,Technology and Engineering ,Wearable ,Acoustics ,reverberation chamber ,01 natural sciences ,UNCERTAINTIES ,Radio spectrum ,[SPI]Engineering Sciences [physics] ,personal exposure ,Calibration ,Dosimetry ,Electrical and Electronic Engineering ,indoor ,Instrumentation ,CALIBRATION ,Physics ,dosimetry ,010401 analytical chemistry ,0104 chemical sciences ,Measurement uncertainty ,Radio frequency ,Antenna (radio) ,EXPOSIMETERS ,Electromagnetic reverberation chamber - Abstract
A multi-band body-worn distributed exposure meter (BWDM) is designed and calibrated for diffuse fields in a reverberation chamber (RC) for personal exposure assessment in indoor environments. The BWDM uses 22 nodes distributed over the torso and measures the incident power density ( $S_{\mathrm{ inc}}$ ) on body for 11 telecommunication bands in the frequency range of 790–5513 MHz. In order to calibrate the measurement device in diffuse fields, a protocol is proposed for on-body calibration of the BWDM. This protocol is applicable to wearable personal exposure meters in general. The BWDM and the proposed calibration protocol are validated in five indoor locations and five frequency bands (the downlink bands at 800, 900, 1800, and 2100 MHz as well as Wi-Fi 2 GHz) using a tri-axial broadband antenna and a spectrum analyzer (SA). The calibration shows that the BWDM has a relatively low measurement uncertainty with a 68% confidence interval on its antenna apertures, in the range 3.4–5.5 dB. A maximum difference of 0.9 dB is obtained for the total exposure in the test areas between the measurements of the BWDM and SA, which is an excellent agreement.
- Published
- 2019
25. The effect of antenna polarization and body morphology on the measurement uncertainty of a wearable multi-band distributed exposure meter
- Author
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Marloes Eeftens, Martin Röösli, Anke Huss, Reza Aminzadeh, René de Seze, Stefan Dongus, Roel Vermeulen, Hendrik Rogier, Luc Martens, Sam Agneessens, Paul Mazet, Elisabeth Cardis, Patrick Van Torre, Matthias Van den Bossche, Arno Thielens, Wout Joseph, Department of Information Technology (INTEC), Universiteit Gent = Ghent University [Belgium] (UGENT), Swiss Tropical and Public Health Institute [Basel], University of Basel (Unibas), Institute for Risk Assessment Sciences [Utrecht, The Netherlands] (IRAS), Utrecht University [Utrecht], Institut National de l'Environnement Industriel et des Risques (INERIS), Périnatalité et Risques Toxiques - UMR INERIS_I 1 (PERITOX), Université de Picardie Jules Verne (UPJV)-CHU Amiens-Picardie-Institut National de l'Environnement Industriel et des Risques, CEntre Technique des Industries Mécaniques (CETIM), CEntre Technique des Industries Mécaniques - Cetim (FRANCE), and Instituto de Salud Global - Institute For Global Health [Barcelona] (ISGlobal)
- Subjects
Electromagnetic field ,Technology and Engineering ,Anechoic chamber ,Acoustics ,Measurement uncertainty ,RF exposure ,Wearable computer ,POLARIZATION DEPENDENCY ,BODY MORPHOLOGY ,Polarization dependency ,01 natural sciences ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,morphology ,Metre ,Electrical and Electronic Engineering ,DIFFUSE ,Physics ,CALIBRATION ,MEASUREMENT UNCERTAINTY ,Personal exposure meters ,PERSONAL EXPOSURE ,010401 analytical chemistry ,Antenna aperture ,PERSONAL EXPOSURE METERS ,RADIOFREQUENCY ELECTROMAGNETIC-FIELDS ,Polarization (waves) ,0104 chemical sciences ,[SDV.TOX]Life Sciences [q-bio]/Toxicology ,RF EXPOSURE ,Body ,Four-frequency ,EXPOSIMETERS - Abstract
This paper studies the effect of antenna polarization on measurement uncertainty of a multi-band body-worn distributed exposure meter (BWDM). The BWDM is a device for assessing electromagnetic fields in real environments accurately. The BWDM consists of 8 nodes and is calibrated on the body for simultaneous measurement of the incident power density in four frequency bands. Each node contains an antenna that can have two potential antenna polarizations.The BWDM is calibrated on four human subjects in an anechoic chamber to determine its measurement uncertainty in terms of 68% confidence interval (CI68) of the on-body antenna aperture. The results show that using a fixed polarization of the antennas on body can lead to a different CI68 up to maximum 4.9 dB when worn by another person which is still 9.6 dB lower than the measurement uncertainty of commercial exposure meters.
- Published
- 2019
26. Topographic mapping of the interfaces between human and aquatic mosquito habitats to enable barrier targeting of interventions against malaria vectors
- Author
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Gerry F. Killeen, Daniel Msellemu, Nicodem J. Govella, Benn Sartorius, Stefan Dongus, Alex J. Limwagu, Yeromin P. Mlacha, Victoria M. Mwakalinga, Prosper P Chaki, and Maureen Coetzee
- Subjects
spatial modelling ,Anopheles gambiae ,030231 tropical medicine ,Plasmodium falciparum ,malaria ,Fencing ,wa_110 ,03 medical and health sciences ,0302 clinical medicine ,parasitic diseases ,medicine ,Earth Science ,030212 general & internal medicine ,Malaria vector ,lcsh:Science ,geophysical topography ,barrier-targeted interventions ,Multidisciplinary ,biology ,Ecology ,Infection prevalence ,Anopheles ,biology.organism_classification ,medicine.disease ,wc_750 ,Habitat ,qx_650 ,qx_510 ,Vector (epidemiology) ,lcsh:Q ,Malaria ,Research Article - Abstract
Geophysical topographic metrics of local water accumulation potential are freely available and have long been known as high-resolution predictors of where aquatic habitats for immature Anopheles mosquitoes are most abundant, resulting in elevated densities of adult malaria vectors and human infection burden. Using existing entomological and epidemiological survey data, here we illustrate how topography can also be used to map out the interfaces between wet, unoccupied valleys and dry, densely populated uplands, where malaria vector densities and infection risk are focally exacerbated. These topographically identifiable geophysical boundaries experience disproportionately high vector densities and malaria transmission risk, because this is where Anopheles mosquitoes first encounter humans when they search for blood after emerging or ovipositing in the valleys. Geophysical topographic indicators accounted for 67% of variance for vector density but for only 43% for infection prevalence, so they could enable very selective targeting of interventions against the former but not the latter (targeting ratios of 5.7 versus 1.5 to 1, respectively). So, in addition to being useful for targeting larval source management to wet valleys, geophysical topographic indicators may also be used to selectively target adult Anopheles mosquitoes with insecticidal residual sprays, fencing, vapour emanators or space sprays to barrier areas along their fringes.
- Published
- 2018
27. A multi-band body-worn distributed radio-frequency exposure meter : design, on-body calibration and study of body morphology
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Luc Martens, René de Seze, Roel Vermeulen, Elisabeth Cardis, Reza Aminzadeh, Marloes Eeftens, Paul Mazet, Stefan Dongus, Wout Joseph, Matthias Van den Bossche, Hendrik Rogier, Anke Huss, Arno Thielens, Martin Röösli, Sam Agneessens, Patrick Van Torre, Institut National de l'Environnement Industriel et des Risques (INERIS), Périnatalité et Risques Toxiques - UMR INERIS_I 1 (PERITOX), Université de Picardie Jules Verne (UPJV)-CHU Amiens-Picardie-Institut National de l'Environnement Industriel et des Risques, One Health Chemisch, dIRAS RA-2, and LS IRAS EEPI ME (Milieu epidemiologie)
- Subjects
AUSTRALIA ,Radiofreqüència ,Radio Waves ,010501 environmental sciences ,lcsh:Chemical technology ,01 natural sciences ,Biochemistry ,UNCERTAINTIES ,BAND ,030218 nuclear medicine & medical imaging ,Analytical Chemistry ,0302 clinical medicine ,Belgium ,measurement uncertainty ,lcsh:TP1-1185 ,Instrumentation ,REAL ,personal exposure meter ,CALIBRATION ,dosimetry ,RADIO FREQUENCY ,Antenna aperture ,Uncertainty ,radio frequency ,DOSIMETRY ,Atomic and Molecular Physics, and Optics ,RF DOSIMETERS ,[SDV.TOX]Life Sciences [q-bio]/Toxicology ,Measurement uncertainty ,Radio frequency ,body morphology ,Radio wave ,EXPOSIMETERS ,Technology and Engineering ,Anechoic chamber ,Frequency band ,Acoustics ,BODY MORPHOLOGY ,ELECTRIC-FIELD ,Radio spectrum ,Article ,ELECTROMAGNETIC-FIELD MEASUREMENTS ,03 medical and health sciences ,Electromagnetic Fields ,calibration ,Radiation Monitoring ,Calibration ,Humans ,Electrical and Electronic Engineering ,Anatomia comparada ,0105 earth and related environmental sciences ,MEASUREMENT UNCERTAINTY ,Comparative anatomy ,PERSONAL EXPOSURE METER ,PERSONAL EXPOSURE ,Environmental science ,ENVIRONMENTS - Abstract
A multi-band Body-Worn Distributed exposure Meter (BWDM) calibrated for simultaneous measurement of the incident power density in 11 telecommunication frequency bands, is proposed. The BDWM consists of 22 textile antennas integrated in a garment and is calibrated on six human subjects in an anechoic chamber to assess its measurement uncertainty in terms of 68% confidence interval of the on-body antenna aperture. It is shown that by using multiple antennas in each frequency band, the uncertainty of the BWDM is 22 dB improved with respect to single nodes on the front and back of the torso and variations are decreased to maximum 8.8 dB. Moreover, deploying single antennas for different body morphologies results in a variation up to 9.3 dB, which is reduced to 3.6 dB using multiple antennas for six subjects with various body mass index values. The designed BWDM, has an improved uncertainty of up to 9.6 dB in comparison to commercially available personal exposure meters calibrated on body. As an application, an average incident power density in the range of 26.7-90.8 muW.m - 2 is measured in Ghent, Belgium. The measurements show that commercial personal exposure meters underestimate the actual exposure by a factor of up to 20.6.
- Published
- 2018
28. Informing new or improved vector control tools for reducing the malaria burden in Tanzania: a qualitative exploration of perceptions of mosquitoes and methods for their control among the residents of Dar es Salaam
- Author
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Stephania Stephen, Zoe Hildon, Caroline Jones, Stefan Dongus, Gerry F. Killeen, Nicodem J. Govella, Salome Kumburu, and Christina Makungu
- Subjects
Male ,Health Knowledge, Attitudes, Practice ,Mosquito Control ,Psychological intervention ,Indoor residual spraying ,Tanzania ,0302 clinical medicine ,Mosquito ,Environmental protection ,Photovoice ,Medicine ,030212 general & internal medicine ,2. Zero hunger ,biology ,1. No poverty ,Middle Aged ,3. Good health ,Mosquito control ,Infectious Diseases ,qx_510 ,Female ,Qualitative ,Larval source management ,Community perceptions ,Adult ,medicine.medical_specialty ,lcsh:Arctic medicine. Tropical medicine ,wc_680 ,lcsh:RC955-962 ,030231 tropical medicine ,Mosquito Vectors ,lcsh:Infectious and parasitic diseases ,Young Adult ,03 medical and health sciences ,Environmental health ,qx_600 ,parasitic diseases ,Repellent ,Humans ,lcsh:RC109-216 ,business.industry ,Research ,Public health ,fungi ,Community Participation ,biology.organism_classification ,medicine.disease ,Focus group ,Bed net ,Vector control ,wc_750 ,Malaria ,Perception ,Parasitology ,business - Abstract
Background The effectiveness of malaria prevention with long-lasting insecticidal nets and indoor residual spraying is limited by emerging insecticide resistance, evasive mosquito behaviours that include outdoor biting, sub-optimal implementation and inappropriate use. New vector control interventions are required and their potential effectiveness will be enhanced if existing household perceptions and practices are integrated into intervention design. Methods This qualitative descriptive study used focus groups discussions, in-depth interviews and photovoice methods to explore mosquito control perceptions and practices among residents in four study sites in Dar es Salaam, Tanzania. Results Mosquitoes were perceived as a growing problem, directly attributed to widespread environmental deterioration and lack of effective mosquito control interventions. Malaria and nuisance biting were perceived as the main problem caused by mosquitoes. Breeding sites were clearly distinguished from resting sites but residents did not differentiate between habitats producing malaria vector mosquitoes and others producing mostly nuisance mosquitoes. The most frequently mentioned protection methods in the wealthiest locations were bed nets, aerosol insecticide sprays, window screens, and fumigation, while bed nets were most frequently mentioned and described as ‘part of the culture’ in the least wealthy locations. Mosquito-proofed housing was consistently viewed as desirable, but considered unaffordable outside wealthiest locations. Slapping and covering up with clothing were most commonly used to prevent biting outdoors. Despite their utility outdoors, topical repellents applied to the skin were considered expensive, and viewed with suspicion due to perceived side effects. Improving the local environment was the preferred method for preventing outdoor biting. Affordability, effectiveness, availability, practicality, as well as social influences, such as government recommendations, socialization and internalization (familiarization and habit) were described as key factors influencing uptake. Conclusions Outdoor transmission is widely accepted as an obstacle to malaria elimination. Larval source management, targeting both malaria vectors and nuisance-biting mosquitoes, is the preferred method for mosquito control among the residents of Dar es Salaam and should be prioritized for development alongside new methods for outdoor personal protection. Even if made available, effective and affordable, these additional interventions may require time and user experience to achieve positive reputations and trustworthiness. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-2056-9) contains supplementary material, which is available to authorized users.
- Published
- 2017
29. The underlying reasons for very high levels of bed net use, and higher malaria infection prevalence among bed net users than non-users in the Tanzanian city of Dar es Salaam: a qualitative study
- Author
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Gerry F. Killeen, Daniel Msellemu, Stefan Dongus, Aloysia Shemdoe, Christina Makungu, Yeromini Mlacha, Khadija Kannady, and Angel Dillip
- Subjects
Health Knowledge, Attitudes, Practice ,Mosquito Control ,lcsh:Arctic medicine. Tropical medicine ,lcsh:RC955-962 ,030231 tropical medicine ,wa_670 ,Non users ,wc_765 ,Tanzania ,wa_110 ,lcsh:Infectious and parasitic diseases ,03 medical and health sciences ,0302 clinical medicine ,Dar es salaam ,parasitic diseases ,qx_600 ,Prevalence ,medicine ,Humans ,lcsh:RC109-216 ,030212 general & internal medicine ,Insecticide-Treated Bednets ,Socioeconomics ,Bed nets ,wa_30 ,biology ,Research ,Infection prevalence ,wa_900 ,biology.organism_classification ,medicine.disease ,Focus group ,Vector control ,Malaria ,3. Good health ,wc_750 ,Infectious Diseases ,Geography ,qx_650 ,qx_510 ,qx_135 ,Female ,Parasitology ,Qualitative research - Abstract
Background\ud Bed nets reduce malaria-related illness and deaths, by forming a protective barrier around people sleeping under them. When impregnated with long-lasting insecticide formulations they also repel or kill mosquitoes attempting to feed upon sleeping humans, and can even suppress entire populations of malaria vectors that feed predominantly upon humans. Nevertheless, an epidemiological study in 2012 demonstrated higher malaria prevalence among bed net users than non-users in urban Dar es Salaam, Tanzania.\ud \ud Methods\ud Focus group discussions were conducted with women from four selected wards of Dar es Salaam city, focusing on four major themes relating to bed net use behaviours: (1) reasons for bed net use, (2) reasons for not using bed nets, (3) stimuli or reminders for people to use a bed net (4) perceived reasons for catching malaria while using a bed net. An analytical method by framework grouping of relevant themes was used address key issues of relevance to the study objectives. Codes were reviewed and grouped into categories and themes.\ud \ud Results\ud All groups said the main reason for bed net use was protection against malaria. Houses with well-screened windows, with doors that shut properly, and that use insecticidal sprays against mosquitoes, were said not to use bed nets, while frequent attacks from malaria was the main stimulus for people to use bed nets. Various reasons were mentioned as potential reasons that compromise bed net efficacy, the most common of which were: (1) bed net sharing by two or more people, especially if one occupant tends to come to bed late at night, and does not tuck in the net 71%; (2) one person shares the bed but does not use the net, moving it away from the side on which s/he sleeps 68%; (3) ineffective usage habits, called ulalavi, in which a sprawling sleeper either touches the net while sleeping up against it or leaves a limb hanging outside of it 68%. Less common reasons mentioned included: (1) Small bed nets which become un-tucked at night (31%); (2) Bed nets with holes large enough to allow mosquitoes to pass (28%); and (3) Going to bed late after already being bitten outdoors (24%).\ud \ud Conclusions\ud Behaviours associated with bed net use like; bed sharing, bed net non compliant-bedfellow, sleeping pattern like ulalavi and some physical bed net attributes compromise its effectiveness and supposedly increase of malaria infection to bed net users. While some well-screened houses looked to instigate low malaria prevalence to non-bed net users.
- Published
- 2017
30. Fine scale mapping of malaria infection clusters by using routinely collected health facility data in urban Dar es Salaam, Tanzania
- Author
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John M. Paliga, Daniel Msellemu, Stefan Dongus, Alex J. Limwagu, Dianne J. Terlouw, Yeromin P. Mlacha, Nicodem J. Govella, Zawadi D. Mageni, Prosper P Chaki, Alpha D. Malishee, Gerry F. Killeen, and Victoria M. Mwakalinga
- Subjects
medicine.medical_specialty ,Health (social science) ,Geographic information system ,030231 tropical medicine ,Geography, Planning and Development ,Psychological intervention ,Medicine (miscellaneous) ,lcsh:G1-922 ,Tanzania ,03 medical and health sciences ,0302 clinical medicine ,Health facility ,Environmental protection ,Environmental health ,parasitic diseases ,Prevalence ,medicine ,Humans ,Hot spots ,030212 general & internal medicine ,biology ,business.industry ,Health Policy ,Public health ,biology.organism_classification ,medicine.disease ,GIS ,Malaria ,Geography ,Local government ,Geographic Information Systems ,Residence ,Spatial heterogeneity ,Health Facilities ,business ,lcsh:Geography (General) - Abstract
This study investigated whether passively collected routine health facility data can be used for mapping spatial heterogeneities in malaria transmission at the level of local government housing cluster administrative units in Dar es Salaam, Tanzania. From June 2012 to January 2013, residential locations of patients tested for malaria at a public health facility were traced based on their local leaders’ names and geo-referencing the point locations of these leaders’ houses. Geographic information systems (GIS) were used to visualise the spatial distribution of malaria infection rates. Spatial scan statistics was deployed to detect spatial clustering of high infection rates. Among 2407 patients tested for malaria, 46.6% (1121) could be traced to their 411 different residential housing clusters. One small spatially aggregated cluster of neighbourhoods with high prevalence was identified. While the home residence housing cluster leader was unambiguously identified for 73.8% (240/325) of malaria-positive patients, only 42.3% (881/2082) of those with negative test results were successfully traced. It was concluded that recording simple points of reference during routine health facility visits can be used for mapping malaria infection burden on very fine geographic scales, potentially offering a feasible approach to rational geographic targeting of malaria control interventions. However, in order to tap the full potential of this approach, it would be necessary to optimise patient tracing success and eliminate biases by blinding personnel to test results.
- Published
- 2017
31. Decreases in adolescents’ figural memory performance associated with cumulative individual radiowave brain dose over one year
- Author
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Arno Thielens, Martin Röösli, Wout Joseph, Milena Foerster, Stefan Dongus, and Marloes Eeftens
- Subjects
Electromagnetic field ,Potential impact ,medicine.medical_specialty ,Technology and Engineering ,Computer science ,business.industry ,Audiology ,Memory performance ,medicine ,General Earth and Planetary Sciences ,Wireless ,business ,Neurocognitive ,Microwave ,General Environmental Science ,Radio wave - Abstract
Background/Aim: The potential impact of microwave radiofrequency electromagnetic fields (RF-EMF) emitted by wireless communication devices on neurocognitive functions of adolescents is still discus...
- Published
- 2017
32. Comprehensive Sterilization of Malaria Vectors Using Pyriproxyfen: A Step Closer to Malaria Elimination
- Author
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Silas Majambere, Stefan Dongus, Caroline Harris, Gerry F. Killeen, Dickson W. Lwetoijera, Samson S. Kiware, and Gregor J. Devine
- Subjects
Mosquito Control ,Pyridines ,Biology ,Toxicology ,chemistry.chemical_compound ,Virology ,Malaria elimination ,Anopheles ,parasitic diseases ,Anopheles arabiensis ,medicine ,Animals ,Malaria vector ,Articles ,Sterilization (microbiology) ,medicine.disease ,Insect Vectors ,Malaria ,Juvenile Hormones ,Cotton cloth ,Mosquito control ,Infectious Diseases ,chemistry ,Infertility ,Cattle ,Female ,Parasitology ,Pyriproxyfen - Abstract
One of the main challenges to malaria elimination is the resilience of vectors, such as Anopheles arabiensis, that evade lethal exposure to insecticidal control measures or express resistance to their active ingredients. This study investigated a novel technology for population control that sterilizes mosquitoes using pyriproxyfen, a juvenile hormone analogue. Females of An. arabiensis were released in a semifield system divided into four equal sections, and each section had a mud hut sheltering a tethered cow providing a blood source for mosquitoes. In all sections, the inner mud hut walls and roofs were lined with black cotton cloth. In one-half of the sections, the cloth was dusted with pyriproxyfen. An overwhelming 96% reduction in adult production was achieved in pyriproxyfen-treated sections compared with control sections. This unprecedented level of control can be exploited to design new vector control strategies that particularly target existing behaviorally resilient and insecticide-resistant populations.
- Published
- 2014
33. Radiofrequency electromagnetic field exposure in everyday microenvironments in Europe: A systematic literature review
- Author
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Seid M. Adem, Sanjay Sagar, Martin Röösli, Milena Foerster, Marloes Eeftens, Benjamin Struchen, Noemi Rebecca Meier, Anna Schoeni, Stefan Dongus, and Katharina Roser
- Subjects
Isi web of science ,animal structures ,Epidemiology ,Radio Waves ,Population ,Transportation ,010501 environmental sciences ,Toxicology ,01 natural sciences ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Exposure level ,Electromagnetic Fields ,Radiation Monitoring ,Environmental health ,Medicine ,Humans ,education ,Simulation ,0105 earth and related environmental sciences ,education.field_of_study ,business.industry ,Public Health, Environmental and Occupational Health ,Environmental Exposure ,Pollution ,Europe ,Systematic review ,Public Health ,business ,Cell Phone ,Environmental Monitoring - Abstract
The impact of the introduction and advancement in communication technology in recent years on exposure level of the population is largely unknown. The main aim of this study is to systematically review literature on the distribution of radiofrequency electromagnetic field (RF-EMF) exposure in the everyday environment in Europe and summarize key characteristics of various types of RF-EMF studies conducted in the European countries. We systematically searched the ISI Web of Science for relevant literature published between 1 January 2000 and 30 April 2015, which assessed RF-EMF exposure levels by any of the methods: spot measurements, personal measurement with trained researchers and personal measurement with volunteers. Twenty-one published studies met our eligibility criteria of which 10 were spot measurements studies, 5 were personal measurement studies with trained researchers (microenvironmental), 5 were personal measurement studies with volunteers and 1 was a mixed methods study combining data collected by volunteers and trained researchers. RF-EMF data included in the studies were collected between 2005 and 2013. The mean total RF-EMF exposure for spot measurements in European "Homes" and "Outdoor" microenvironments was 0.29 and 0.54 V/m, respectively. In the personal measurements studies with trained researchers, the mean total RF-EMF exposure was 0.24 V/m in "Home" and 0.76 V/m in "Outdoor". In the personal measurement studies with volunteers, the population weighted mean total RF-EMF exposure was 0.16 V/m in "Homes" and 0.20 V/m in "Outdoor". Among all European microenvironments in "Transportation", the highest mean total RF-EMF 1.96 V/m was found in trains of Belgium during 2007 where more than 95% of exposure was contributed by uplink. Typical RF-EMF exposure levels are substantially below regulatory limits. We found considerable differences between studies according to the type of measurements procedures, which precludes cross-country comparison or evaluating temporal trends. A comparable RF-EMF monitoring concept is needed to accurately identify typical RF-EMF exposure levels in the everyday environment.
- Published
- 2016
34. The epidemiology of residual Plasmodium falciparum malaria transmission and infection burden in an African city with high coverage of multiple vector control measures
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Daniel Msellemu, Neil F. Lobo, Zacharia Mtema, Chris Drakeley, Yeromin P. Mlacha, Gerry F. Killeen, Hagai I. Namango, Nicodem J. Govella, Silas Majambere, Stefan Dongus, Prosper P Chaki, Samson S. Kiware, Alex J. Ntamatungiro, and Victoria M. Mwakalinga
- Subjects
Male ,Plasmodium ,Mosquito Control ,Long-lasting insecticidal net ,Tanzania ,0302 clinical medicine ,Mosquito ,Epidemiology ,Prevalence ,030212 general & internal medicine ,Longitudinal Studies ,Artemisinin ,Malaria, Falciparum ,Child ,2. Zero hunger ,Aged, 80 and over ,Middle Aged ,3. Good health ,Chronic infection ,Infectious Diseases ,Child, Preschool ,Female ,Larval source management ,medicine.drug ,Adult ,medicine.medical_specialty ,Adolescent ,030231 tropical medicine ,wc_765 ,Biology ,wa_110 ,03 medical and health sciences ,Young Adult ,Internal medicine ,qx_600 ,Anopheles ,parasitic diseases ,medicine ,Disease Transmission, Infectious ,Animals ,Humans ,Aged ,Research ,Infant, Newborn ,wa_240 ,Infant ,Plasmodium falciparum ,Odds ratio ,biology.organism_classification ,medicine.disease ,Confidence interval ,Vector control ,Malaria ,Cross-Sectional Studies ,Window screening ,qx_135 ,Immunology ,Tropical medicine ,Africa ,Housing ,Parasitology - Abstract
Background In the Tanzanian city of Dar es Salaam, high coverage of long-lasting insecticidal nets (LLINs), larvicide application (LA) and mosquito-proofed housing, was complemented with improved access to artemisinin-based combination therapy and rapid diagnostic tests by the end of 2012. Methods Three rounds of city-wide, cluster-sampled cross-sectional surveys of malaria parasite infection status, spanning 2010 to 2012, were complemented by two series of high-resolution, longitudinal surveys of vector density. Results Larvicide application using a granule formulation of Bacillus thuringiensis var. israelensis (Bti) had no effect upon either vector density (P = 0.820) or infection prevalence (P = 0.325) when managed by a private-sector contractor. Infection prevalence rebounded back to 13.8 % in 2010, compared with
- Published
- 2016
35. Malaria vectors and their blood-meal sources in an area of high bed net ownership in the western Kenya highlands
- Author
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Bryson A. Ndenga, Nicholas Mulaya, Joan N. Shiroko, Ulrike Fillinger, Sandra K. Musaki, and Stefan Dongus
- Subjects
Veterinary medicine ,medicine.medical_specialty ,Entomology ,Anopheles gambiae ,030231 tropical medicine ,wa_110 ,03 medical and health sciences ,0302 clinical medicine ,parasitic diseases ,medicine ,Animals ,Humans ,030212 general & internal medicine ,Insecticide-Treated Bednets ,Domestication ,2. Zero hunger ,biology ,business.industry ,Research ,Ownership ,wa_240 ,Blood meal ,biology.organism_classification ,medicine.disease ,Kenya ,3. Good health ,wc_750 ,Malaria ,Infectious Diseases ,Parasitology ,qx_650 ,Tropical medicine ,Livestock ,business - Abstract
Background: Blood-meal sources of malaria vectors affect their capacity to transmit the disease. Most efficient malaria vectors prefer human hosts. However, with increasing personal protection measures it becomes more difficult for them to find human hosts. Here recent malaria vector blood-meal sources in western Kenya highlands were investigated.Methods: Adult mosquitoes resting indoors, outdoors and exiting through windows were collected in three study areas within the western Kenya highlands from June 2011 to June 2013. A census of people, livestock and of insecticide-treated nets was done per house. Mosquito blood-meal sources were determined as human, goat, bovine or chicken using enzyme-linked-immunosorbent assays.Results: Most (86.3 %) households possessed at least one bed net, 57.2 % had domesticated animals and 83.6 % had people sharing houses with livestock at night. Most (94.9 %) unfed malaria vectors were caught exiting through windows. Overall, 53.1 % of Anopheles gambiae sensu stricto obtained blood-meals from humans, 26.5 % from goats and 18.4 % from bovines. Single blood-meal sources by An. gambiae s.s. from humans were 26.5 %, 8.2 % from bovines and 2.0 % from goats. Mixed blood-meal sources by An. gambiae s.s. identified included: 24.5 % human/goat, 10.2 % human/bovine, 8.2 % human/bovine/goat and also 8.2 % bovine/goat. One An. arabiensis mosquito obtained blood-meal only from humans.Conclusion: An unusually high frequency of animal and mixed human-animal blood meals in the major malaria vector An. gambiae s.s. was revealed in the western Kenya highlands where bed net coverage is above the WHO target. The shift in blood-meal sources from humans to livestock is most likely the vectors’ response to increased bed net coverage and the close location of livestock frequently in the same house as people at night. Livestock-targeted interventions should be considered under these circumstances to address residual malaria transmission.
- Published
- 2016
36. Spatially aggregated clusters and scattered smaller loci of elevated malaria vector density and human infection prevalence in urban Dar es Salaam, Tanzania
- Author
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Victoria M. Mwakalinga, Yeromin P. Mlacha, Zawadi D. Mageni, Benn Sartorius, Nicodem J. Govella, Gerry F. Killeen, Stefan Dongus, Maureen Coetzee, John M. Paliga, Alex J. Limwagu, and Daniel Msellemu
- Subjects
medicine.medical_specialty ,Anopheles gambiae ,030231 tropical medicine ,Plasmodium falciparum ,wc_765 ,Tanzania ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,Mosquito ,law ,parasitic diseases ,Anopheles ,medicine ,Prevalence ,Animals ,Cluster Analysis ,Humans ,030212 general & internal medicine ,Malaria, Falciparum ,biology ,Research ,wa_240 ,biology.organism_classification ,medicine.disease ,Spatial clustering ,Virology ,Confidence interval ,Vector control ,3. Good health ,Insect Vectors ,Malaria ,Transmission (mechanics) ,Infectious Diseases ,Cross-Sectional Studies ,qx_650 ,Mapping ,wb_700 ,Vector (epidemiology) ,Tropical medicine ,Parasitology ,Hotspots ,Cartography - Abstract
Background: Malaria transmission, primarily mediated by Anopheles gambiae, persists in Dar es Salaam (DSM) despite high coverage with bed nets, mosquito-proofed housing and larviciding. New or improved vector control strategies are required to eliminate malaria from DSM, but these will only succeed if they are delivered to the minority of locations where residual transmission actually persists. Hotspots of spatially clustered locations with elevated malaria infection prevalence or vector densities were, therefore, mapped across the city in an attempt to provide a basis for targeting supplementary interventions.Methods: Two phases of a city-wide population-weighted random sample of cross-sectional household surveys of malaria infections were complemented by two matching phases of geographically overlapping, high-resolution, longitudinal vector density surveys; spanning 2010–2013. Spatial autocorrelations were explored using Moran’s I and hotspots were detected using flexible spatial scan statistics.Results: Seven hotspots of spatially clustered elevated vector density and eight of malaria infection prevalence were detected over both phases. Only a third of vectors were collected in hotspots in phase 1 (30 %) and phase 2 (33 %). Malaria prevalence hotspots accounted for only half of malaria infections detected in phase 1 (55 %) and phase 2 (47 %). Three quarters (76 % in phase 1 and 74 % in phase 2) of survey locations with detectable vector populations were outside of hotspots. Similarly, more than half of locations with higher infection prevalence (>10 %) occurred outside of hotspots (51 % in phase 1 and 54 % in phase 2). Vector proliferation hazard (exposure to An. gambiae) and malaria infection risk were only very loosely associated with each other (Odds ratio (OR) [95 % Confidence Interval (CI)] = 1.56 [0.89, 1.78], P = 0.52)).Conclusion: Many small, scattered loci of local malaria transmission were haphazardly scattered across the city, so interventions targeting only currently identifiable spatially aggregated hotspots will have limited impact. Routine, spatially comprehensive, longitudinal entomological and parasitological surveillance systems, with sufficient sensitivity and spatial resolution to detect these scattered loci, are required to eliminate transmission from this typical African city. Intervention packages targeted to both loci and hotspots of transmission will need to suppress local vector proliferation, treat infected residents and provide vulnerable residents with supplementary protective measures against exposure.
- Published
- 2015
37. Building multi‐layered resilience in a malaria control programme in Dar es Salaam, Tanzania
- Author
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Stefan Dongus, Constanze Pfeiffer, Selemani Mbuyita, Emmy Metta, and Brigit Obrist
- Subjects
biology ,business.industry ,Environmental resource management ,Mosquito breeding ,Development ,biology.organism_classification ,medicine.disease ,Urban malaria ,Tanzania ,Dar es salaam ,medicine ,Business ,Communication skills ,Malaria control ,Environmental planning ,Competence (human resources) ,Malaria - Abstract
This study applied the multi‐layered social resilience framework in the context of an urban malaria control programme by using a qualitative approach. It was found that exchange between and within administrative levels supported resilience‐building processes in terms of mosquito breeding site elimination. ‘Reactive’ and ‘proactive’ capacities were successfully built among programme staff. However, more potential could be tapped among local leaders and household members, by increasing their competence in eliminating breeding sites of malaria vectors. Improving the communication skills of the programme’s field workers might support such processes. Together with local leaders, they could act as multipliers of sensitisation messages.
- Published
- 2010
38. Dynamics and sustainability of urban agriculture: examples from sub-Saharan Africa
- Author
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Stefan Dongus and Pay Drechsel
- Subjects
Sustainable land management ,Global and Planetary Change ,Health (social science) ,Sociology and Political Science ,Ecology ,Land use ,Natural resource economics ,Geography, Planning and Development ,Urban density ,Management, Monitoring, Policy and Law ,Geography ,Urban planning ,Urban climate ,Sustainability ,Urban ecosystem ,Urban agriculture ,Water resource management ,Nature and Landscape Conservation - Abstract
Urban agriculture can have many different expressions, varying from backyard gardening to poultry and livestock farming. This article focuses on crop production on larger open spaces in cities of sub-Saharan Africa (SSA) and investigates the sustainability and dynamics of this type of land use, which is common on undeveloped plots particularly in lowlands, such as in inland valleys, or along urban streams or drains. An adapted version of the Framework for Evaluating Sustainable Land Management (FESLM) developed by the Food and Agriculture Organization of the United Nations (FAO) was used to assess the sustainability of urban agriculture. As an example for dynamics, the spatio-temporal changes of open-space agriculture in Dar es Salaam, Tanzania, are analyzed for the period from 1992 to 2005, and compared with data from other cities. Crop production on urban open spaces appears as a market-driven, highly productive and profitable phenomenon. However, it is often constrained by tenure insecurity and non-agricultural land demands. Also, the common use of polluted water limits the official support of irrigated urban farming. However, despite these constraints, the phenomenon of urban farming appears persistent and resilient to its changing environment, although individual farmers might have to shift to other sites when their plots are needed for construction. Open-space vegetable production in urban areas is a dynamic, viable and largely sustainable livelihood strategy, especially for poor urban dwellers. Spatio-temporal analysis shows that it is not a short-lived or transitional phenomenon—probably as long as it can maintain its comparative market advantage. However, its informal nature and resulting lack of political recognition need to be addressed.
- Published
- 2009
39. Mapping hotspots of malaria transmission from pre-existing hydrology, geology and geomorphology data in the pre-elimination context of Zanzibar, United Republic of Tanzania
- Author
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Mwinyi I. Msellem, Mark W. Smith, Christopher Thomas, Zawadi D. Mageni, Stefan Dongus, Mark G. Macklin, Andy Hardy, Abdullah S. Ali, Silas Majambare, Gerry F. Killeen, and Abdul-wahiyd H Al-mafazy
- Subjects
Wet season ,Water flow ,Rain ,Geographic Mapping ,Context (language use) ,Land cover ,Mosquito breeding habitat ,Tanzania ,wa_110 ,Hydrology (agriculture) ,Dry season ,parasitic diseases ,medicine ,Animals ,Humans ,Geomorphology ,Hydrology ,geography ,geography.geographical_feature_category ,Geography ,Research ,Geology ,wc_755 ,15. Life on land ,Karst ,medicine.disease ,Vector control ,wc_750 ,3. Good health ,Insect Vectors ,Malaria ,Infectious Diseases ,qx_510 ,Larva ,Regression Analysis ,Parasitology ,F810 Environmental Geography ,Seasons ,F840 Physical Geography ,Larval source management - Abstract
Background\ud \ud Larval source management strategies can play an important role in malaria elimination programmes, especially for tackling outdoor biting species and for eliminating parasite and vector populations when they are most vulnerable during the dry season. Effective larval source management requires tools for identifying geographic foci of vector proliferation and malaria transmission where these efforts may be concentrated. Previous studies have relied on surface topographic wetness to indicate hydrological potential for vector breeding sites, but this is unsuitable for karst (limestone) landscapes such as Zanzibar where water flow, especially in the dry season, is subterranean and not controlled by surface topography.\ud \ud Methods\ud \ud We examine the relationship between dry and wet season spatial patterns of diagnostic positivity rates of malaria infection amongst patients reporting to health facilities on Unguja, Zanzibar, with the physical geography of the island, including land cover, elevation, slope angle, hydrology, geology and geomorphology in order to identify transmission hot spots using Boosted Regression Trees (BRT) analysis.\ud \ud Results\ud \ud The distribution of both wet and dry season malaria infection rates can be predicted using freely available static data, such as elevation and geology. Specifically, high infection rates in the central and southeast regions of the island coincide with outcrops of hard dense limestone which cause locally elevated water tables and the location of dolines (shallow depressions plugged with fine-grained material promoting the persistence of shallow water bodies).\ud \ud Conclusions\ud \ud This analysis provides a tractable tool for the identification of malaria hotspots which incorporates subterranean hydrology, which can be used to target larval source management strategies.
- Published
- 2015
40. Long-term trends in Anopheles gambiae insecticide resistance in Côte d’Ivoire
- Author
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Stefan Dongus, Eliézer K. N’Goran, Bassirou Bonfoh, Akré M. Adja, Louise G. Bellai, Sarah Barry, Hilary Ranson, Constant Edi, Paul C. D. Johnson, Pie Müller, Mouhamadou Chouaibou, David Weetman, and Benjamin G. Koudou
- Subjects
Insecticides ,Entomology ,Anopheles gambiae ,030231 tropical medicine ,Indoor residual spraying ,Review ,wc_765 ,Biology ,Organochlorine ,Insecticide Resistance ,Toxicology ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Organophosphate ,Malaria intervention ,qx_600 ,Anopheles ,parasitic diseases ,Animals ,Bioassay ,030304 developmental biology ,Multiple resistance ,2. Zero hunger ,0303 health sciences ,Pyrethroid ,Resistance (ecology) ,wa_240 ,biology.organism_classification ,Vector control ,wc_750 ,3. Good health ,Cote d'Ivoire ,Infectious Diseases ,Parasitology ,chemistry ,Insecticide resistance ,kdr ,Carbamate ,Insect Proteins ,qx_515 - Abstract
Background Malaria control is heavily dependent on the use of insecticides that target adult mosquito vectors via insecticide treated nets (ITNs) or indoor residual spraying (IRS). Four classes of insecticide are approved for IRS but only pyrethroids are available for ITNs. The rapid rise in insecticide resistance in African malaria vectors has raised alarms about the sustainability of existing malaria control activities. This problem might be particularly acute in Côte d’Ivoire where resistance to all four insecticide classes has recently been recorded. Here we investigate temporal trends in insecticide resistance across the ecological zones of Côte d’Ivoire to determine whether apparent pan-African patterns of increasing resistance are detectable and consistent across insecticides and areas. Methods We combined data on insecticide resistance from a literature review, and bioassays conducted on field-caught Anopheles gambiae mosquitoes for the four WHO-approved insecticide classes for ITN/IRS. The data were then mapped using Geographical Information Systems (GIS) and the IR mapper tool to provide spatial and temporal distribution data on insecticide resistance in An. gambiae sensu lato from Côte d’Ivoire between 1993 and 2014. Results Bioassay mortality decreased over time for all insecticide classes, though with significant spatiotemporal variation, such that stronger declines were observed in the southern ecological zone for DDT and pyrethroids than in the central zone, but with an apparently opposite effect for the carbamate and organophosphate. Variation in relative abundance of the molecular forms, coupled with dramatic increase in kdr 1014F frequency in M forms (An. coluzzii) seems likely to be a contributory factor to these patterns. Although records of resistance across insecticide classes have become more common, the number of classes tested in studies has also increased, precluding a conclusion that multiple resistance has also increased. Conclusion Our analyses attempted synthesis of 22 years of bioassay data from Côte d’Ivoire, and despite a number of caveats and potentially confounding variables, suggest significant but spatially-variable temporal trends in insecticide resistance. In the light of such spatio-temporal dynamics, regular, systematic and spatially-expanded monitoring is warranted to provide accurate information on insecticide resistance for control programme management. Electronic supplementary material The online version of this article (doi:10.1186/s13071-014-0500-z) contains supplementary material, which is available to authorized users.
- Published
- 2014
41. Increasing role of Anopheles funestus and Anopheles arabiensis in malaria transmission in the Kilombero Valley, Tanzania
- Author
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Silas Majambere, Gregor J. Devine, Stefan Dongus, Philip J. McCall, Caroline Harris, Samson S. Kiware, and Dickson W. Lwetoijera
- Subjects
Rural Population ,Plasmodium ,Veterinary medicine ,Anopheles gambiae ,Tanzania ,Polymerase Chain Reaction ,Insecticide Resistance ,chemistry.chemical_compound ,Funestus ,Insecticide ,EIR ,Surveillance ,Anopheles ,Infectious Diseases ,Sporozoites ,Epidemiological Monitoring ,Arabiensis ,qx_515 ,medicine.drug ,Bendiocarb ,Antigens, Protozoan ,Enzyme-Linked Immunosorbent Assay ,Biology ,wa_110 ,Gambiae ,qx_600 ,parasitic diseases ,medicine ,Transmission ,Animals ,Humans ,Research ,wa_240 ,DNA, Protozoan ,medicine.disease ,biology.organism_classification ,Virology ,Vector control ,Malaria ,Insect Vectors ,wc_750 ,Cyhalothrin ,Deltamethrin ,chemistry ,Susceptibility ,Vector (epidemiology) ,Kilombero ,Parasitology ,Vector ,Season ,Permethrin - Abstract
Background\ud \ud In order to sustain the gains achieved by current malaria control strategies, robust surveillance systems that monitor dynamics of vectors and their roles in malaria transmission over time are essential. This longitudinal study demonstrates the trends in malaria vector dynamics and their relative contribution to malaria transmission in hyperendemic transmission settings in Tanzania.\ud \ud Methods\ud \ud The study was conducted in two villages within the Kilombero Valley, in rural Tanzania for five consecutive years (2008–2012). Seventy-two houses were selected per village and each house was sampled for mosquitoes monthly using a CDC light trap. Collected mosquitoes were assessed for species identity and sporozoite infection status using PCR and ELISA, respectively. Anopheles funestus and Anopheles arabiensis susceptibility to insecticides was assessed using WHO guidelines.\ud \ud Results\ud \ud A total of 100,810 malaria vectors were collected, of which 76% were Anopheles gambiae s. l. and 24% were An. funestus. Of all An. funestus samples that amplified with PCR (n = 2,737), 97% were An. funestus s.s., 2% were Anopheles rivorulum and 1% Anopheles leesoni. Whereas for An. gambiae s.l. (n = 8,117), 93% were An. arabiensis and 7% were Anopheles gambiae s.s. The proportion of An. gambiae s.s. identified by PCR (2,924) declined from 0.2% in the year 2008 to undetectable levels in 2012. Malaria transmission intensity significantly decreased from an EIR of 78.14 infectious bites/person/year in 2008 to 35 ib/p/yr in 2011 but rebounded to 226 ib/p/yr in 2012 coinciding with an increased role of An. funestus in malaria transmission. Insecticide susceptibility tests indicated high levels of resistance in An. funestus against deltamethrin (87%), permethrin (65%), lambda cyhalothrin (74%), bendiocarb (65%), and DDT (66%). Similarly, An. arabiensis showed insecticide resistance to deltamethrin (64%), permethrin (77%) and lambda cyhalothrin (42%) in 2014.\ud \ud Conclusion\ud \ud The results indicate the continuing role of An. arabiensis and the increasing importance of An. funestus in malaria transmission, and pyrethroid resistance development in both species. Complementary vector control and surveillance tools are needed that target the ecology, behaviour and insecticide resistance management of these vector species, in order to preserve the efficacy of LLINs.
- Published
- 2014
42. An affordable, quality-assured community-based system for high-resolution entomological surveillance of vector mosquitoes that reflects human malaria infection risk patterns
- Author
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Tanya L. Russell, Daniel Msellemu, Zacharia Mtema, Gerry F. Killeen, Neil F. Lobo, Athuman Muhili, Nicodem J. Govella, Ying Zhou, Yeromin P. Mlacha, Prosper P Chaki, Samson S. Kiware, Stefan Dongus, and Alpha D. Malishee
- Subjects
Veterinary medicine ,Mosquito Control ,lcsh:Arctic medicine. Tropical medicine ,lcsh:RC955-962 ,media_common.quotation_subject ,Disease Vectors ,Sensitivity and Specificity ,Tanzania ,law.invention ,lcsh:Infectious and parasitic diseases ,Public health surveillance ,law ,Environmental health ,parasitic diseases ,medicine ,Animals ,Humans ,Quality (business) ,Public Health Surveillance ,lcsh:RC109-216 ,media_common ,Tropical Climate ,Surveillance, monitoring, evaluation ,biology ,Research ,Community Participation ,medicine.disease ,biology.organism_classification ,Mosquito control ,Infectious Diseases ,Transmission (mechanics) ,Culicidae ,Vector (epidemiology) ,Community health ,Parasitology ,Community Health ,Entomology ,Malaria - Abstract
Background More sensitive and scalable entomological surveillance tools are required to monitor low levels of transmission that are increasingly common across the tropics, particularly where vector control has been successful. A large-scale larviciding programme in urban Dar es Salaam, Tanzania is supported by a community-based (CB) system for trapping adult mosquito densities to monitor programme performance. Methodology An intensive and extensive CB system for routine, longitudinal, programmatic surveillance of malaria vectors and other mosquitoes using the Ifakara Tent Trap (ITT-C) was developed in Urban Dar es Salaam, Tanzania, and validated by comparison with quality assurance (QA) surveys using either ITT-C or human landing catches (HLC), as well as a cross-sectional survey of malaria parasite prevalence in the same housing compounds. Results Community-based ITT-C had much lower sensitivity per person-night of sampling than HLC (Relative Rate (RR) [95% Confidence Interval (CI)] = 0.079 [0.051, 0.121], P Anopheles gambiae s.l. and 0.153 [0.137, 0.171], P An. gambiae or Culex respectively). Despite the poor sensitivity of the ITT per night of sampling, when CB-ITT was compared with QA-HLC, it proved at least comparably sensitive in absolute terms (171 versus 169 primary vectors caught) and cost-effective (153US$ versus 187US$ per An. gambiae caught) because it allowed more spatially extensive and temporally intensive sampling (4284 versus 335 trap nights distributed over 615 versus 240 locations with a mean number of samples per year of 143 versus 141). Despite the very low vectors densities (Annual estimate of about 170 An gambiae s.l bites per person per year), CB-ITT was the only entomological predictor of parasite infection risk (Odds Ratio [95% CI] = 4.43[3.027,7. 454] per An. gambiae or Anopheles funestus caught per night, P =0.0373). Discussion and conclusion CB trapping approaches could be improved with more sensitive traps, but already offer a practical, safe and affordable system for routine programmatic mosquito surveillance and clusters could be distributed across entire countries by adapting the sample submission and quality assurance procedures accordingly.
- Published
- 2012
43. Participatory Mapping as a Component of Operational Malaria Vector Control in Tanzania
- Author
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Gerry F. Killeen, Stefan Dongus, Marcel Tanner, Victoria M. Mwakalinga, and Khadija Kannady
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geography ,geography.geographical_feature_category ,biology ,Workload ,Urban area ,biology.organism_classification ,Sketch ,Field (computer science) ,Variety (cybernetics) ,Tanzania ,Information system ,Environmental planning ,Cartography ,Level of detail - Abstract
Global efforts to tackle malaria have gained unprecedented momentum. However, in order to move towards the ambitious goal of eliminating and eventually eradicating malaria, existing tools must be improved and new tools developed. The City of Dar es Salaam, Tanzania, is home to the first operational community-based larviciding programme targeting malaria vectors in modern Africa. In an attempt to optimize the accuracy of the application of larvicides, a participatory mapping and monitoring approach was introduced that includes (1) community-based development of sketch maps of the target areas, and (2) verification of the sketch maps using laminated aerial photographs in the field which are later digitized and analyzed using Geographical Information Systems (GIS). The participatory mapping approach developed enables gap-free coverage of targeted areas with mosquito larval habitat control, and more equal distribution of the workload of field staff. The procedure has been tested, validated and successfully applied in 56 km2 of the city area. Currently, the approach is being scaled up to an area of about eight times that size, thus covering most of the urban area of Dar es Salaam. The procedure is simple, straightforward, replicable and at relatively low cost. It requires only minimal technical skills and equipment. In the case of Dar es Salaam, the resulting database provides a spatial resolution of administrative boundaries that is almost 50 times higher than that of previously available data. This level of detail can be very useful for a wide range of other purposes rather than merely malaria control, for example implementation of council programmes in a variety of sectors and spatially-explicit analyses for research and evaluation purposes.
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- 2011
44. A tool box for operational mosquito larval control: preliminary results and early lessons from the Urban Malaria Control Programme in Dar es Salaam, Tanzania
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Stefan Dongus, Steven W. Lindsay, Nico J Govella, Ulrike Fillinger, Evan M. Mathenge, Dickson Nyika, Hassan Mshinda, Gerry F. Killeen, Prosper P Chaki, Burton H. Singer, Deo Mtasiwa, Khadija Kannady, Yvonne Geissbühler, Marcia C. Castro, Michael J Vanek, Marcel Tanner, and George William
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Program evaluation ,lcsh:Arctic medicine. Tropical medicine ,Mosquito Control ,lcsh:RC955-962 ,Anopheles gambiae ,Population ,Bacillus thuringiensis ,Efficiency, Organizational ,Tanzania ,lcsh:Infectious and parasitic diseases ,Environmental protection ,Environmental health ,Anopheles ,parasitic diseases ,medicine ,Animals ,Humans ,lcsh:RC109-216 ,Pest Control, Biological ,education ,Ecosystem ,education.field_of_study ,biology ,Methodology ,Monitoring and evaluation ,biology.organism_classification ,medicine.disease ,Vector control ,Malaria ,Mosquito control ,Infectious Diseases ,Larva ,Parasitology ,Health Services Research - Abstract
Background As the population of Africa rapidly urbanizes, large populations could be protected from malaria by controlling aquatic stages of mosquitoes if cost-effective and scalable implementation systems can be designed. Methods A recently initiated Urban Malaria Control Programme in Dar es Salaam delegates responsibility for routine mosquito control and surveillance to modestly-paid community members, known as Community-Owned Resource Persons (CORPs). New vector surveillance, larviciding and management systems were designed and evaluated in 15 city wards to allow timely collection, interpretation and reaction to entomologic monitoring data using practical procedures that rely on minimal technology. After one year of baseline data collection, operational larviciding with Bacillus thuringiensis var. israelensis commenced in March 2006 in three selected wards. Results The procedures and staff management systems described greatly improved standards of larval surveillance relative to that reported at the outset of this programme. In the first year of the programme, over 65,000 potential Anopheles habitats were surveyed by 90 CORPs on a weekly basis. Reaction times to vector surveillance at observations were one day, week and month at ward, municipal and city levels, respectively. One year of community-based larviciding reduced transmission by the primary malaria vector, Anopheles gambiae s.l., by 31% (95% C.I. = 21.6–37.6%; p = 0.04). Conclusion This novel management, monitoring and evaluation system for implementing routine larviciding of malaria vectors in African cities has shown considerable potential for sustained, rapidly responsive, data-driven and affordable application. Nevertheless, the true programmatic value of larviciding in urban Africa can only be established through longer-term programmes which are stably financed and allow the operational teams and management infrastructures to mature by learning from experience.
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- 2008
45. Participatory mapping of target areas to enable operational larval source management to suppress malaria vector mosquitoes in Dar es Salaam, Tanzania
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Dickson Nyika, Hassan Mshinda, Axel Drescher, Khadija Kannady, Marcia C. Castro, Marcel Tanner, Deo Mtasiwa, Stefan Dongus, Gerry F. Killeen, and Ulrike Fillinger
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Mosquito Control ,Urban Population ,General Computer Science ,Population ,Business, Management and Accounting(all) ,lcsh:Computer applications to medicine. Medical informatics ,Tanzania ,Dar es salaam ,parasitic diseases ,medicine ,Animals ,Humans ,Malaria vector ,education ,Environmental planning ,Ecosystem ,Larva ,education.field_of_study ,biology ,fungi ,Methodology ,Public Health, Environmental and Occupational Health ,medicine.disease ,biology.organism_classification ,General Business, Management and Accounting ,Participatory mapping ,Vector control ,Insect Vectors ,Malaria ,Mosquito control ,Culicidae ,Geography ,Epidemiological Monitoring ,Geographic Information Systems ,lcsh:R858-859.7 ,Topography, Medical ,Environmental Monitoring ,Computer Science(all) - Abstract
Background Half of the population of Africa will soon live in towns and cities where it can be protected from malaria by controlling aquatic stages of mosquitoes. Rigorous but affordable and scaleable methods for mapping and managing mosquito habitats are required to enable effective larval control in urban Africa. Methods A simple community-based mapping procedure that requires no electronic devices in the field was developed to facilitate routine larval surveillance in Dar es Salaam, Tanzania. The mapping procedure included (1) community-based development of sketch maps and (2) verification of sketch maps through technical teams using laminated aerial photographs in the field which were later digitized and analysed using Geographical Information Systems (GIS). Results Three urban wards of Dar es Salaam were comprehensively mapped, covering an area of 16.8 km2. Over thirty percent of this area were not included in preliminary community-based sketch mapping, mostly because they were areas that do not appear on local government residential lists. The use of aerial photographs and basic GIS allowed rapid identification and inclusion of these key areas, as well as more equal distribution of the workload of malaria control field staff. Conclusion The procedure developed enables complete coverage of targeted areas with larval control through comprehensive spatial coverage with community-derived sketch maps. The procedure is practical, affordable, and requires minimal technical skills. This approach can be readily integrated into malaria vector control programmes, scaled up to towns and cities all over Tanzania and adapted to urban settings elsewhere in Africa.
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- 2007
46. Urban agriculture and Anopheles habitats in Dar es Salaam, Tanzania
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Khadija Kannady, Marcel Tanner, Gerry F. Killeen, Axel Drescher, Stefan Dongus, Ulrike Fillinger, Laura Gosoniu, Dickson Nyika, Hassan Mshinda, Marcia C. Castro, and Deo Mtasiwa
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Irrigation ,Health (social science) ,Urban Population ,Geography, Planning and Development ,lcsh:G1-922 ,Medicine (miscellaneous) ,Tanzania ,Anopheles ,parasitic diseases ,Animals ,Seedbed ,Urban agriculture ,Parasite Egg Count ,Ecosystem ,biology ,Agroforestry ,Ecology ,business.industry ,Health Policy ,fungi ,food and beverages ,Sowing ,Climate & environment ,Gardening ,biology.organism_classification ,Vector control ,Cross-Sectional Studies ,Logistic Models ,Geography ,Habitat ,Agriculture ,Larva ,urban agriculture, Anopheles larvae, geographical information systems, malaria risk, malaria control, Tanzania ,business ,lcsh:Geography (General) - Abstract
A cross-sectional survey of agricultural areas, combined with routinely monitored mosquito larval information, was conducted in urban Dar es Salaam, Tanzania, to investigate how agricultural and geographical features may influence the presence of Anopheles larvae. Data were integrated into a geographical information systems framework, and predictors of the presence of Anopheles larvae in farming areas were assessed using multivariate logistic regression with independent random effects. It was found that more than 5% of the study area (total size 16.8 km2) was used for farming in backyard gardens and larger open spaces. The proportion of habitats containing Anopheles larvae was 1.7 times higher in agricultural areas compared to other areas (95% confidence interval = 1.56-1.92). Significant geographic predictors of the presence of Anopheles larvae in gardens included location in lowland areas, proximity to river, and relatively impermeable soils. Agriculture-related predictors comprised specific seedbed types, mid-sized gardens, irrigation by wells, as well as cultivation of sugar cane or leafy vegetables. Negative predictors included small garden size, irrigation by tap water, rainfed production and cultivation of leguminous crops or fruit trees. Although there was an increased chance of finding Anopheles larvae in agricultural sites, it was found that breeding sites originated by urban agriculture account for less than a fifth of all breeding sites of malaria vectors in Dar es Salaam. It is suggested that strategies comprising an integrated malaria control effort in malaria-endemic African cities include participatory involvement of farmers by planting shade trees near larval habitats.
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- 2009
47. Community-owned resource persons for malaria vector control: enabling factors and challenges in an operational programme in Dar es Salaam, United Republic of Tanzania
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Gerry F. Killeen, Ulrike Fillinger, Stefan Dongus, Ann H. Kelly, and Prosper P Chaki
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medicine.medical_specialty ,Resource (biology) ,Public Administration ,030231 tropical medicine ,Human Resources ,wa_395 ,Health administration ,03 medical and health sciences ,0302 clinical medicine ,qx_600 ,parasitic diseases ,medicine ,030212 general & internal medicine ,Socioeconomics ,Social policy ,lcsh:R5-920 ,biology ,business.industry ,lcsh:Public aspects of medicine ,Research ,Public health ,fungi ,Health services research ,Public Health, Environmental and Occupational Health ,lcsh:RA1-1270 ,biology.organism_classification ,Vector control ,wa_100 ,3. Good health ,Mosquito control ,Tanzania ,qx_650 ,Local government ,Optometry ,lcsh:Medicine (General) ,business - Abstract
Background Community participation in vector control and health services in general is of great interest to public health practitioners in developing countries, but remains complex and poorly understood. The Urban Malaria Control Program (UMCP) in Dar es Salaam, United Republic of Tanzania, implements larval control of malaria vector mosquitoes. The UMCP delegates responsibility for routine mosquito control and surveillance to community-owned resource persons (CORPs), recruited from within local communities via the elected local government. Methods A mixed method, cross-sectional survey assessed the ability of CORPs to detect mosquito breeding sites and larvae, and investigated demographic characteristics of the CORPs, their reasons for participating in the UMCP, and their work performance. Detection coverage was estimated as the proportion of wet habitats found by the investigator which had been reported by CORP. Detection sensitivity was estimated as the proportion of wet habitats found by the CORPS which the investigator found to contain Anopheles larvae that were also reported to be occupied by the CORP. Results The CORPs themselves perceived their role as professional rather than voluntary, with participation being a de facto form of employment. Habitat detection coverage was lower among CORPs that were recruited through the program administrative staff, compared to CORPs recruited by local government officials or health committees (Odds Ratio = 0.660, 95% confidence interval = [0.438, 0.995], P = 0.047). Staff living within their areas of responsibility had > 70% higher detection sensitivity for both Anopheline (P = 0.016) and Culicine (P = 0.012): positive habitats compared to those living outside those same areas. Discussion and conclusions Improved employment conditions as well as involving the local health committees in recruiting individual program staff, communication and community engagement skills are required to optimize achieving effective community participation, particularly to improve access to fenced compounds. A simpler, more direct, less extensive community-based surveillance system in the hands of a few, less burdened, better paid and maintained program personnel may improve performance and data quality.
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48. Sterilising effects of pyriproxyfen on Anopheles arabiensis and its potential use in malaria control
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Gregor J. Devine, Lena M. Lorenz, Caroline Harris, Nancy S. Matowo, Silas Majambere, Stefan Dongus, and Dickson W. Lwetoijera
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Insecticides ,Sterilisation ,Mosquito Control ,Time Factors ,Pyridines ,Offspring ,media_common.quotation_subject ,Fertility ,Biology ,Toxicology ,chemistry.chemical_compound ,Anopheles ,medicine ,Animals ,Humans ,media_common ,Research ,Feeding Behavior ,Blood meal ,medicine.disease ,biology.organism_classification ,Fecundity ,Survival Analysis ,Vector control ,Malaria ,Anopheles arabiensis ,Mosquito control ,Infectious Diseases ,chemistry ,Pyriproxyfen ,Female ,Parasitology - Abstract
BACKGROUND: Insecticide resistance poses a major threat to current vector control campaigns. Insecticides with novel modes of action are therefore in high demand. Pyriproxyfen (PPF), a conventional mosquito pupacide, has a unique mode of action that also sterilises adult mosquitoes (unable to produce viable offspring) upon direct contact. However, the timing of PPF exposure in relation to when mosquitoes take a blood meal has an important impact on that sterilisation. This study investigated the relationship between different blood feeding and PPF exposure timings to determine the potential of PPF sterilisation in controlling Anopheles arabiensis. METHODS: Four treatment regimens were investigated: blood fed three days before PPF exposure (A), blood fed one day before PPF exposure (B), blood fed one day after PPF exposure (C) and blood fed three days after PPF exposure (D) for their impact on egg laying (fecundity) and the production of viable offspring (fertility), while the impact of PPF exposure on mosquito survival was investigated in the absence of a blood meal. All regimens and the survival study exposed mosquitoes to PPF via the bottle assay at 3 mg AI/m(2) for 30 minutes. RESULTS: Female mosquitoes that blood-fed one day prior to PPF exposure (regimen B), produced no viable offspring during that gonotrophic cycle (100% reduction in fertility). All other treatments had no significant effect. The observed reductions in fecundity and fertility were caused by the retention of eggs (97% of eggs retained, i.e. produced in the ovaries but not laid, in regimen B, p = 0.0004). Some of these retained eggs were deformed in shape. PPF exposure on mosquito survival in the absence of a blood meal was found to have no effect. CONCLUSIONS: The results presented here suggest that sterilising adult malaria vectors using PPF could form part of a malaria control strategy, taking advantage of the lack of reported resistance to PPF in mosquitoes and its unique mode of action. We propose that targeting resting mosquitoes, which are highly susceptible to PPF at low doses, is the optimal direction for developing this control tool.
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49. A need for better housing to further reduce indoor malaria transmission in areas with high bed net coverage
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Gregor J. Devine, Silas Majambere, Stefan Dongus, Zawadi D. Mageni, Caroline Harris, Samson S. Kiware, and Dickson W. Lwetoijera
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Rural Population ,Insecticides ,Veterinary medicine ,Mosquito Control ,House risk factors ,Eaves ,Indoor residual spraying ,Biology ,Tanzania ,law.invention ,Anopheles funestus ,Risk Factors ,law ,Environmental health ,Anopheles ,parasitic diseases ,medicine ,Anopheles gambiae s.l ,Animals ,Humans ,Insecticide-Treated Bednets ,Netting ,Aerosols ,Population Density ,Research ,biology.organism_classification ,medicine.disease ,ITNs ,Vector control ,Malaria ,Insect Vectors ,Mosquito control ,Transmission (mechanics) ,Infectious Diseases ,Housing ,Female ,Parasitology - Abstract
Background The suppression of indoor malaria transmission requires additional interventions that complement the use of insecticide treated nets (ITNs) and indoor residual spraying (IRS). Previous studies have examined the impact of house structure on malaria transmission in areas of low transmission. This study was conducted in a high transmission setting and presents further evidence about the association between specific house characteristics and the abundance of endophilic malaria vectors. Methods Mosquitoes were sampled using CDC light traps from 72 randomly selected houses in two villages on a monthly basis from 2008 to 2011 in rural Southern Tanzania. Generalized linear models using Poisson distributions were used to analyze the association of house characteristics (eave gaps, wall types, roof types, number of windows, rooms and doors, window screens, house size), number of occupants and ITN usage with mean catches of malaria vectors (An.gambiae s.l. and An. funestus). Results A total of 36490 female An. gambiae s.l. were collected in Namwawala village and 21266 in Idete village. As for An. funestus females, 2268 were collected in Namwawala and 3398 in Idete. Individually, each house factor had a statistically significant impact (p
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50. Effective autodissemination of pyriproxyfen to breeding sites by the exophilic malaria vector Anopheles arabiensis in semi-field settings in Tanzania
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Silas Majambere, Dickson W. Lwetoijera, Stefan Dongus, Gregor J. Devine, Samson S. Kiware, Philip J. McCall, and Caroline Harris
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Veterinary medicine ,Insecticides ,Mosquito Control ,Pyridines ,wa_395 ,Semi-field system ,wc_765 ,Autodissemination ,Tanzania ,wa_110 ,chemistry.chemical_compound ,qx_600 ,Anopheles ,medicine ,Anopheles arabiensis ,Animals ,Malaria vector ,Clay pots ,Ecosystem ,biology ,business.industry ,Research ,fungi ,wa_240 ,biology.organism_classification ,medicine.disease ,Vector control ,Biotechnology ,Malaria ,Insect Vectors ,Pupa ,Mosquito control ,Infectious Diseases ,qx_650 ,chemistry ,Pyriproxyfen ,Africa ,Female ,Parasitology ,qx_515 ,business - Abstract
BACKGROUND\ud Malaria vector control strategies that target adult female mosquitoes are challenged by the emergence of insecticide resistance and behavioural resilience. Conventional larviciding is restricted by high operational costs and inadequate knowledge of mosquito-breeding habitats in rural settings that might be overcome by the juvenile hormone analogue, Pyriproxyfen (PPF). This study assessed the potential for Anopheles arabiensis to pick up and transfer lethal doses of PPF from contamination sites to their breeding habitats (i.e. autodissemination of PPF).\ud \ud METHODS\ud A semi-field system (SFS) with four identical separate chambers was used to evaluate PPF-treated clay pots for delivering PPF to resting adult female mosquitoes for subsequent autodissemination to artificial breeding habitats within the chambers. In each chamber, a tethered cow provided blood meals to laboratory-reared, unfed female An. arabiensis released in the SFS. In PPF-treated chambers, clay pot linings were dusted with 0.2 - 0.3 g AI PPF per pot. Pupae were removed from the artificial habitats daily, and emergence rates calculated. Impact of PPF on emergence was determined by comparing treatment with an appropriate control group.\ud \ud RESULTS\ud Mean (95%CI) adult emergence rates were (0.21 +/- 0.299) and (0.95 +/- 0.39) from PPF-treated and controls respectively (p < 0.0001). Laboratory bioassay of water samples from artificial habitats in these experiments resulted in significantly lower emergence rates in treated chambers (0.16 +/- 0.23) compared to controls 0.97 +/- 0.05) (p < 0.0001). In experiments where no mosquitoes introduced, there were no significant differences between control and treatment, indicating that transfer of PPF to breeding sites only occurred when mosquitoes were present; i.e. that autodissemination had occurred. Treatment of a single clay pot reduced adult emergence in six habitats to (0.34 +/- 0.13) compared to (0.98 +/- 0.02) in the controls (p < 0.0001), showing a high level of habitats coverage amplification of the autodissemination event.\ud \ud CONCLUSION\ud The study provides proof of principle for the autodissemination of PPF to breeding habitats by malaria vectors. These findings highlight the potential for this technique for outdoor control of malaria vectors and call for the testing of this technique in field trials.
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