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Background: In the past decade, there has been rapid scale-up of insecticide-based malaria vector control in the context of integrated vector management (IVM) according to World Health Organization recommendations. Endemic countries have deployed indoor residual spraying (IRS) and long-lasting insecticidal nets as hallmark vector control interventions. This paper discusses the successes and continued challenges and the way forward for the IRS programme in Malawi. Case description: The National Malaria Control Programme in Malawi, with its efforts to implement an integrated approach to malaria vector control, was the 'case' for this study. Information sources included all available data and accessible archived documentary records on IRS in Malawi. A methodical assessment of published and unpublished documents was conducted via a literature search of online electronic databases. Discussion: Malawi has implemented IRS as the main malaria transmission-reducing intervention. However, pyrethroid and carbamate resistance in malaria vectors has been detected extensively across the country and has adversely affected the IRS programme. Additionally, IRS activities have been characterized by substantial inherent logistical and technical challenges culminating into missed targets. As a consequence, programmatic IRS operations have been scaled down from seven districts in 2010 to only one district in 2014. The future of the IRS programme in Malawi is uncertain due to limited funding, high cost of alternative insecticides and technical resource challenges being experienced in the country. Conclusions: The availability of a long-lasting formulation of the organophosphate pirimiphos-methyl makes the re-introduction of IRS a possibility and may be a useful approach for the management of pyrethroid resistance. Implementing the IVM strategy, advocating for sustainable domestic funding, including developing an insecticide resistance monitoring and management plan and vector surveillance guidelines will be pivotal in steering entomologic monitoring and future vector control activities in Malawi. [ABSTRACT FROM AUTHOR]

Background: Owing to pyrethroid resistance in An. gambiae, the carbamate and organophosphate insecticides are currently regarded as alternatives or supplements to pyrethroids for use on mosquito net treatments. Resistance monitoring is therefore essential to investigate the susceptibility of An. gambiae s.l to these alternative products. Methods: Two to three day old adult female Anopheles mosquitoes were reared from larvae collected in the five districts (Kouandé, Natitingou, Matéri, Péhunco, Tanguiéta) of the Atacora department. Mosquitoes were then exposed to WHO impregnated papers. The four treatments consisted of: carbamates (0.1% bendiocarb, 0.1% propoxur) and organophosphates (0.25% pirimiphosmethyl, 1% fenitrothion). PCR assays were run to determine the members of the An. gambiae complex, the molecular forms (M) and (S), as well as phenotypes for insensitive acetylcholinesterase (AChE1) due to ace-1R mutation. Results: Bioassays showed bendiocarb resistance in all populations of An. gambiae s.s. tested. Propoxur resistance was observed in Matéri, Péhunco and Tanguiéta, while it was suspected in Kouandé and Natitingou. As for the organophosphates, susceptibility to pirimiphos-methyl was assessed in all populations. Fenitrothion resistance was detected in Kouandé, Péhunco and Tanguiéta, while it was suspected in Matéri and Natitingou. The S-form was predominant in tested samples (94.44%). M and S molecular forms were sympatric but no M/S hybrids were detected. The ace-1R mutation was found in both S and M molecular forms with frequency from 3.6 to 12%. Although the homozygous resistant genotype was the most prevalent genotype among survivors, the genotypes could not entirely explain the bioassay results. Conclusion: Evidence of bendiocarb resistance in An. gambiae populations is a clear indication that calls for the implementation of insecticide resistance management strategies. The ace-1R mutation could not entirely explain the resistance to bendiocarb observed and is highly suggestive of involvement of other resistance mechanisms such as metabolic detoxification. [ABSTRACT FROM AUTHOR]

Rice cultivation in Sub-Saharan Africa produces a negative externality in the form of higher malaria risk. Larval source management, such as the application of bio-larvicides in rice fields, is available to mitigate the problem. However, the cost of larvicide and the corresponding spraying campaigns is such that rice farmers are unable to carry all of the financial burden themselves. This study explores in a rice-growing area of Rwanda whether, and to what extent, local consumers are willing to share this burden through their consumption choices. In a non-incentivized format, we elicit willingness-to-pay from 290 respondents for locally produced rice that is cultivated in either sprayed or non-sprayed fields. Price premium estimates are extracted to discuss the prospects of a voluntary sustainability standard for 'malaria-free' rice. We observe robust support among local consumers to re-align food production and public health through the marketplace. The results thus warrant a critical reflection on the assumption in the ethical consumption literature that consumers in the Global South, especially those on low incomes in rural areas, cannot play their part. [ABSTRACT FROM AUTHOR]

Background: For centuries malaria infection remains a public health burden globally as well as in the Sunyani Municipality. This exploratory qualitative study aimed to assess the prospects of environmental management and sanitation (EMS) as a malaria vector control strategy among key stakeholders involved in the prevention and control of malaria in Sunyani Municipality, Ghana. Method: We used an exploratory qualitative study and a designed focus group discussion (FGD) guide (with specific research questions) to solicit opinions and/or views among Malaria Control Focal Persons, Environmental Health Officers (Health Inspectors), and Honourable Assembly Members. Data were collected between December 2019 and February 2020. The responses were analyzed according to the specific research questions. Result: Findings from this study shows that high government support and/or political will by investing in environmental sanitation infrastructure, creating the enabling environment for strict enforcement of environmental sanitation bye-laws by Environmental Health Officers/Health Inspectors, effective and efficient collaboration among key stakeholders and organization of communal labor activities is likely to help reduce the majority of the mosquito breeding sites. Conclusion: The prospects of environmental management and sanitation (EMS) as a vector control strategy, look promisingly very high, pertinent, and workable and a likelihood game changer of winning the fight against malaria due to the residual transmission that is happening outdoors. However, EMS can be employed as a supplementary method to the current core vector control methods if the following conditions and bottlenecks are addressed and in place: (a) Effective collaboration among key stakeholders at all levels; (b) Adequate allocation of funds to the Environmental Health and Sanitation Department; (c) Enactment of robust educational campaigns across all educational levels and via different media; (d) Recognition, empowerment, and adequate resourcing of Environmental Health Officers; (e) Adherence to the building regulations to prevent encroachment of natural wetlands; (f) Revision of fees/fines and prosecution of sanitary offenders; (g) Enactment of an Environmental Sanitation Day (ESD), and establishment of the Environmental Health and Sanitation Fund (EHSF). [ABSTRACT FROM AUTHOR]

BACKGROUND: For centuries malaria infection remains a public health burden globally as well as in the Sunyani Municipality. This exploratory qualitative study aimed to assess the prospects of environmental management and sanitation (EMS) as a malaria vector control strategy among key stakeholders involved in the prevention and control of malaria in Sunyani Municipality, Ghana. METHOD: We used an exploratory qualitative study and a designed focus group discussion (FGD) guide (with specific research questions) to solicit opinions and/or views among Malaria Control Focal Persons, Environmental Health Officers (Health Inspectors), and Honourable Assembly Members. Data were collected between December 2019 and February 2020. The responses were analyzed according to the specific research questions. RESULT: Findings from this study shows that high government support and/or political will by investing in environmental sanitation infrastructure, creating the enabling environment for strict enforcement of environmental sanitation bye-laws by Environmental Health Officers/ Health Inspectors, effective and efficient collaboration among key stakeholders and organization of communal labor activities is likely to help reduce the majority of the mosquito breeding sites. CONCLUSION: The prospects of environmental management and sanitation (EMS) as a vector control strategy, look promisingly very high, pertinent, and workable and a likelihood game changer of winning the fight against malaria due to the residual transmission that is happening outdoors. However, EMS can be employed as a supplementary method to the current core vector control methods if the following conditions and bottlenecks are addressed and in place: (a) Effective collaboration among key stakeholders at all levels; (b) Adequate allocation of funds to the Environmental Health and Sanitation Department; (c) Enactment of robust educational campaigns across all educational levels and via different media; (d) Recognition, empowerment, and adequate resourcing of Environmental Health Officers; (e) Adherence to the building regulations to prevent encroachment of natural wetlands; (f) Revision of fees/fines and prosecution of sanitary offenders; (g) Enactment of an Environmental Sanitation Day (ESD), and establishment of the Environmental Health and Sanitation Fund (EHSF). [ABSTRACT FROM AUTHOR]

Background: Integrated vector management (IVM) is the recommended approach for controlling some vectorborne diseases (VBD). In the face of current challenges to disease vector control, IVM is vital to achieve national targets set for VBD control. Though global efforts, especially for combating malaria, now focus on elimination and eradication, IVM remains useful for Uganda which is principally still in the control phase of the malaria continuum. This paper outlines the processes undertaken to consolidate tactical planning and implementation frameworks for IVM in Uganda. Case description: The Uganda National Malaria Control Programme with its efforts to implement an IVM approach to vector control was the 'case' for this study. Integrated management of malaria vectors in Uganda remained an underdeveloped component of malaria control policy. In 2012, knowledge and perceptions of malaria vector control policy and IVM were assessed, and recommendations for a specific IVM policy were made. In 2014, a thorough vector control needs assessment (VCNA) was conducted according to WHO recommendations. The findings of the VCNA informed the development of the national IVM strategic guidelines. Information sources for this study included all available data and accessible archived documentary records on VBD control in Uganda. The literature was reviewed and adapted to the local context and translated into the consolidated tactical framework. Discussion: WHO recommends implementation of IVM as the main strategy to vector control and has encouraged member states to adopt the approach. However, many VBD-endemic countries lack IVM policy frameworks to guide implementation of the approach. In Uganda most VBD coexists and could be managed more effectively if done in tandem. In order to successfully control malaria and other VBD and move towards their elimination, the country needs to scale up proven and effective vector control interventions and also learn from the experience of other countries. The IVM strategy is important in consolidating inter-sectoral collaboration and coordination and providing the tactical direction for effective deployment of vector control interventions along the five key elements of the approach and to align them with contemporary epidemiology of VBD in the country. Conclusions: Uganda has successfully established an evidence-based IVM approach and consolidated strategic planning and operational frameworks for VBD control. However, operating implementation arrangements as outlined in the national strategic guidelines for IVM and managing insecticide resistance, as well as improving vector surveillance, are imperative. In addition, strengthened information, education and communication/behaviour change and communication, collaboration and coordination will be crucial in scaling up and using vector control interventions. [ABSTRACT FROM AUTHOR]

Abstract: Environmental exposure to persistent organic pollutants (POPs) may cause detrimental health effects in the population with the developing foetus and infants being at highest risk. This paper reports on the findings of the pilot study that took place in seven geographical regions of South Africa, 96 pregnant women admitted for delivery participated in the study. The following selected POPs were analysed in maternal plasma: 15 polychlorinated biphenyls (PCBs) congeners (IUPAC No. 28, 52, 99, 101, 105, 118, 138, 149, 153, 156, 170, 180, 183, 187, 194); six DDT metabolites (dichlordiphenyltrichloroethane p,p''-DDT and o,p''-DDT; diphenyldichloroethylene p,p''-DDE and o,p''-DDE, dichlorophenylethane p,p''-DDD o,p''-DDD) and other pesticides such as hexachlorocyclohexanes (α-HCH, β-HCH, γ-HCH), hexachlorobenzene (HCB), heptachlor, chlordanes (t-CD and c-CD), nanochlors (t-NC and c-NC) and mirex. The overall results showed large regional differences with the rural site having the lowest levels for all measured contaminants. The levels of PCB congeners were found to be low in all samples and across all sites. DDT metabolites were detected in most participants of this study and large regional differences were evident. Two malaria endemic sites, where indoor residual spraying (IRS) with DDT takes place to control malaria vector, were included in the study. The highest levels of DDTs were measured in the coastal malaria site (Indian Ocean) with geometric means of 5177ng/g lipid and 1797ng/g lipid for p,p''-DDE and p,p''-DDT, and 1966ng/g lipid and 726ng/g lipid for p,p''-DDE and p,p''-DDT in inland malaria site. γ-HCH was found to be elevated overall, except for the urban community; the highest levels were measured in the inland and coastal malaria sites. p,p''-DDT and γ-HCH were however not correlated, indicating different sources. The high DDT levels in the malaria spraying regions as well as the elevated γ-HCH levels are of concern and call for extended monitoring of women and children in selected regions. [Copyright &y& Elsevier]

Background: Resistance in malaria vectors to pyrethroids, the most widely used class of insecticides for malaria vector control, threatens the continued efficacy of vector control tools. Target-site resistance is an important genetic resistance mechanism caused by mutations in the voltage-gated sodium channel (Vgsc) gene that encodes the pyrethroid target-site. Understanding the geographic distribution of target-site resistance, and temporal trends across different vector species, can inform strategic deployment of vector control tools. Results: We develop a Bayesian statistical spatiotemporal model to interpret species-specific trends in the frequency of the most common resistance mutations, Vgsc-995S and Vgsc-995F, in three major malaria vector species Anopheles gambiae, An. coluzzii, and An. arabiensis over the period 2005–2017. The models are informed by 2418 observations of the frequency of each mutation in field sampled mosquitoes collected from 27 countries spanning western and eastern regions of Africa. For nine selected countries, we develop annual predictive maps which reveal geographically structured patterns of spread of each mutation at regional and continental scales. The results show associations, as well as stark differences, in spread dynamics of the two mutations across the three vector species. The coverage of ITNs was an influential predictor of Vgsc allele frequencies, with modelled relationships between ITN coverage and allele frequencies varying across species and geographic regions. We found that our mapped Vgsc allele frequencies are a significant partial predictor of phenotypic resistance to the pyrethroid deltamethrin in An. gambiae complex populations. Conclusions: Our predictive maps show how spatiotemporal trends in insecticide target-site resistance mechanisms in African An. gambiae vary across individual vector species and geographic regions. Molecular surveillance of resistance mechanisms will help to predict resistance phenotypes and track their spread. [ABSTRACT FROM AUTHOR]

Background: Anopheles arabiensis is a major malaria vector, recently implicated as contributing to ongoing residual malaria transmission in South Africa, which feeds and rests both indoors and outdoors. This species is, therefore, not effectively targeted using core malaria vector control interventions alone. Additionally, increasing resistance to available insecticides necessitates investigations into complementary non-insecticide-based vector control methods for outdoor-resting mosquitoes. The feasibility of the sterile insect technique (SIT) as a complementary vector control intervention is being investigated in South Africa. Successful implementation of an SIT programme largely depends on inundating a target insect population with sterilized laboratory-bred males. Therefore, knowledge of the native population size and dispersal ability of released sterile laboratory-reared males is critical. In this study, we estimated the male An. arabiensis population size and the dispersal of released males in an area targeted for a pilot sterile male release programme. Methods: Three separate releases were performed within a 2-year period. Approximately 5000–15,000 laboratory-reared male An. arabiensis (KWAG) were produced and marked for mark–release–recapture experiments. To recapture released mosquitoes, cloth tubes were deployed in widening concentric circles. The average dispersal distance of released males was calculated and the wild male An. arabiensis population size was estimated using two Lincoln index formulae. The natural population was sampled concurrently and Anopheles species diversity examined. Results: The Anopheles gambiae complex and An. funestus group species made up the majority of wild collections along with other anophelines. The An. arabiensis population size was estimated to be between 550 and 9500 males per hectare depending on time of year, weather conditions and method used. Average dispersal distance of marked males ranged from 58 to 86 m. Marked males were found in swarms with wild males, indicating that laboratory-reared males are able to locate and participate in mating swarms. Conclusions: It was logistically feasible to conduct mark–release–recapture studies at the current scale. The population size estimates obtained may provide a guideline for the initial number of males to use for a pending SIT pilot trial. It is promising for future SIT trials that laboratory-reared marked males participated in natural swarms, appearing at the right place at the right time. [ABSTRACT FROM AUTHOR]

Abstract: Health research ethics has its roots in protecting individuals participating in clinical trials. There is, however, nascent interest in ethics in public health, although it does not yet cover ethics in the development of public health products. The paper reviews the history of the development of malaria vector interventions, which initially aimed at promoting colonial interests. Attempts at eradicating malaria in Africa ended in 1969, and DDT, the leading malaria vector control tool was banned soon after. Insecticide Treated Nets, which later gave rise to Long Lasting Insecticidal Nets have resurrected malaria mosquito vector control, and their development has set new benchmarks, which it is suggested should be followed by all vector control tools under development. Furthermore, DDT has been exonerated and is back in the vector control arsenal. New tools under development include the sterile male technique, genetically modified mosquitoes, entomopathogenic fungi, and odorants.The paper proposes that these new tools be tested in community settings, abiding by all the leading bioethical principles, and calls for the development and implementation of international ethical guidelines for trials in public health. [Copyright &y& Elsevier]

Background: The successful control of malaria vectors requires the control of both the larval and adult stages. The adult control methods through indoor residual spraying (IRS) and use of long-lasting insecticidal nets (LLINs) continue to be widely used with some high measure of success. Larval control methods are also being used by a number of National Malaria Control Programmes (NMCPs) with limited understanding of its contribution. Larval control might be needed in some areas to move from malaria control to elimination. This experimental study was conducted to assess the field effectiveness of winter larviciding on the larval stages of the mosquito in Botswana and Zimbabwe. Methods: Two villages were selected in each of the two countries, one as an intervention and the other as the control. Water bodies in the intervention villages were treated using the commercial product VectoBac® WG (Valent BioSciences Corporation, IL, USA) containing the active ingredient Bacillus thuringiensis var. israelensis (Bti), a WHO recommended bio-larvicide, applied at a rate of 300 g per hectare. Random-effects Poisson regression was employed during data analysis to compare intervention with control sites with respect to larval counts. Results: The average marginal effect of larviciding on the mosquito larvae taking interaction with time (period) into account, was -1.94 (95% CI -2.42 to -1.46) with incidence rate ratio of 0.14, thus an 86% larval reduction attributable to the intervention for both countries combined. There was a 92% and 65% effect for Botswana and Zimbabwe respectively. The effect on the early larval and late stages was 77% (P < 0.001) and 91% (P < 0.001), respectively. Overall, intervention larval sampling points had five more larvae than the control at baseline and 26 less after 16 weeks. The effect on the different species also showed similar trends. Discussion/conclusion: Larval control using Bti showed a high effect on the population of the mosquito larvae. The reduction of the early and late larval stages can lead to reduced adult mosquito emergence and low adult mosquito densities. Larviciding can be used to control mosquito vector population by suppressing the larval stages thereby reducing adult emergence and malaria risk. [ABSTRACT FROM AUTHOR]

Background: Knowledge on the spread and distribution of insecticide resistance in major malaria vectors such as Anopheles funestus is key to implement successful resistance management strategies across Africa. Here, by assessing the susceptibility status of an inland population of An. funestus Giles (Kpome) and investigating molecular basis of resistance, we show that multiple resistance and consistent plasmodium infection rate are present in Anopheles funestus populations from Kpome. Methods: The insecticide susceptibility level of collected Anopheles funestus was assessed. Synergist (PBO) was used to screen resistance mechanisms. The TaqMan technique was used for genotyping of insecticide resistant alleles and detecting plasmodium infection levels. The nested PCR was used to further assess the plasmodium infection rate. Results: The TaqMan analysis of plasmodial infections revealed an infection rate (18.2 %) of An. funestus in this locality. The WHO bioassays revealed a multiple phenotypic resistance profile for An. funestus in Kpome. This population is highly resistant to pyrethroids (permethrin and deltamethrin), organochlorines (DDT), and carbamates (bendiocarb). A reduced susceptibility was observed with dieldrin. Mortalities did not vary after pre-exposure to PBO for DDT indicating that cytochrome P450s play little role in DDT resistance in Kpome. In contrast, we noticed, a significant increase in mortalities when PBO was combined to permethrin suggesting the direct involvement of P450s in pyrethroid resistance. A high frequency of the L119F-GSTe2 DDT resistance marker was observed in the wild DDT resistant population (9 %RS and 91 %RR) whereas the A296S mutation was detected at a low frequency (1 %RS and 99 %SS). Conclusion: The presence of multiple resistance in An. funestus populations in the inland locality of Kpome is established in this study as recently documented in the costal locality of Pahou. Data from both localities suggest that resistance could be widespread in Benin and this highlights the need for further studies to assess the geographical distribution of insecticide resistance across Benin and neighboring countries as well as a more comprehensive analysis of the resistance mechanisms involved. [ABSTRACT FROM AUTHOR]

Background: South Africa uses indoor residual spraying (IRS) for vector control in its malaria control programme (MCP). Insecticide-treated wall linings (ITWLs) offer possible advantages over IRS and long-lasting, insecticide-treated nets (LLINs). This study assessed the user acceptability and perceived effectiveness, and the durability, including efficacy through bioassays, of a newly developed, monofilament polyethylene ITWL. Methods: Four ITWL formulations/treatments, two incorporated with deltamethrin and two with alpha-cypermethrin in concentrations ranging from 0.29 to 0.85 wt%, and untreated linings were randomly installed on the inner walls of traditional mud huts (n = 20) and modern brick houses (n = 20) in a community village in Vhembe District, Limpopo Province. The linings were exposed to conditions within these dwellings over 6 months. Data were collected monthly through questionnaires and entomological residual efficacy analysis of ITWL, as part of durability testing, was done bimonthly using WHO prescribed bioassays. Results: Monofilament polyethylene ITWLs were successfully installed in traditional sleeping huts and in bedrooms of modern type brick houses. ITWL remained intact throughout the entire 6 months of the study. Participants did not express any dissatisfaction towards the linings although two participants indicated the product should be fitted at a lower level for better results. User perceived effectiveness was very high with participants reporting observed mortality of mosquitoes and other nuisance insects. This perception coincided with results obtained through residual efficacy bioassays where a 100 % knockdown and mortality of mosquitoes was recorded throughout the trial period. Acceptability regarding appearance, including colour, position and attachment method, was also satisfactory with some participants citing the lining as decorative. All participants opted to keep ITWL and residual long-term efficacy will be determined annually for a further 3 years. Conclusions: The newly developed ITWLs are highly accepted amongst participants in an unsprayed section of a village in a malaria-endemic area. The perceived effectiveness that coincides with results obtained through bioassays and acceptance of the overall appearance of ITWL will be evaluated over a longer term to determine sustainability. With further developing and testing, this ITWL has the potential to become a sustainable and safer alternative vector control method. [ABSTRACT FROM AUTHOR]

Background Knowledge of the ecology and behaviour of a target species is a prerequisite for the successful development of any vector control strategy. Before the implementation of any strategy it is essential to have comprehensive information on the bionomics of species in the targeted area. The aims of this study were to conduct regular entomological surveillance and to determine the relative abundance of anopheline species in the northern Kruger National Park. In addition to this, the impact of weather conditions on an Anopheles arabiensis population were evaluated and a range of mosquito collection methods were assessed. Methods A survey of Anopheles species was made between July 2010 and December 2012. Mosquitoes were collected from five sites in the northern Kruger National Park, using carbon dioxide-baited traps, human landing and larval collections. Specimens were identified morphologically and polymerase chain reaction assays were subsequently used where appropriate. Results A total of 3,311 specimens belonging to nine different taxa was collected. Species collected were: Anopheles arabiensis (n = 1,352), Anopheles quadriannulatus (n = 70), Anopheles coustani (n = 395), Anopheles merus (n = 349), Anopheles pretoriensis (n = 35), Anopheles maculipalpis (n = 28), Anopheles rivulorum (n = 19), Anopheles squamosus (n = 3) and Anopheles rufipes (n = 2). Members of the Anopheles gambiae species complex were the most abundant and widely distributed, occurring across all collection sites. The highest number of mosquitoes was collected using CO2 baited net traps (58.2%) followed by human landing catches (24.8%). Larval collections (17%) provided an additional method to increase sample size. Mosquito sampling productivity was influenced by prevailing weather conditions and overall population densities fluctuated with seasons. Conclusion Several anopheline species occur in the northern Kruger National Park and their densities fluctuate between seasons. Species abundance and relative proportions within the An. gambiae complex varied between collection methods. There is a perennial presence of an isolated population of An. arabiensis at the Malahlapanga site which declined in density during the dry winter months, making this site suitable for a small pilot study site for SIT as a malaria vector control strategy. [ABSTRACT FROM AUTHOR]

Background Integrated vector management (IVM) based vector control is encouraged by the World Health Organization (WHO). However, operational experience with the IVM strategy has mostly come from countries with relatively well-established health systems and with malaria control focused programmes. Little is known about deployment of IVM for combating multiple vector-borne diseases in post-emergency settings, where delivery structures are less developed or absent. This manuscript reports on the feasibility of operational IVM for combating vector-borne diseases in South Sudan. A methodical review of published and unpublished documents on vector-borne diseases for South Sudan was conducted via systematic literature search of online electronic databases, Google Scholar, PubMed and WHO, using a combination of search terms. Additional, nonpeer reviewed literature was examined for information related to the subject. Discussion South Sudan is among the heartlands of vector-borne diseases in the world, characterized by enormous infrastructure, human and financial resource constraints and a weak health system against an increasing number of refugees, returnees and internally displaced people. The presence of a multiplicity of vector-borne diseases in this post-conflict situation presents a unique opportunity to explore the potential of a rational IVM strategy for multiple disease control and optimize limited resource utilization, while maximizing the benefits and providing a model for countries in a similar situation. Conclusion The potential of integrating vector-borne disease control is enormous in South Sudan. However, strengthened coordination, intersectoral collaboration and institutional and technical capacity for entomological monitoring and evaluation, including enforcement of appropriate legislation are crucial. [ABSTRACT FROM AUTHOR]

The concentrations of dichlorodiphenyltrichloroethane (DDT) compounds in cord blood of 214 children born between 2003 and 2006 in Manhiça (Mozambique) have been determined. In this time interval, corresponding to the period before DDT reintroduction for indoor residual spraying, the observed values averaged 0.8 and 0.4 ng/ml for 4,4′-dichlorodiphenyldichloroethylene (4,4′-DDE) and 4,4′-DDT, respectively, and were similar to those found in western countries. However, the 4,4′-DDT/4,4′-DDE ratio was high indicating that the inputs of these compounds arriving to children in utero originated from recent uses of the insecticide. The strongest factor affecting DDT concentration was parity. A well-defined decreasing concentration trend was observed for the cord blood concentrations in the period of study. The trend was also observed for multiparae and primiparae mothers independently. Children from multiparae women showed much lower concentrations than primiparae women. Children from mothers with secondary school level exhibited lower concentrations of these pesticides than mothers with lower degree of education. [ABSTRACT FROM AUTHOR]

Understanding how multiple insecticide resistance mechanisms occur in malaria vectors is essential for efficient vector control. This study aimed at assessing the evolution of metabolic mechanisms and Kdr L995F/S resistance alleles in Anopheles gambiae s.l. from North Cameroon, following long-lasting insecticidal nets (LLINs) distribution in 2011. Female An. gambiae s.l. emerging from larvae collected in Ouro-Housso/Kanadi, Be-Centre, and Bala in 2011 and 2015, were tested for susceptibility to deltamethrin + piperonyl butoxide (PBO) or SSS-tributyl-phosphoro-thrithioate (DEF) synergists, using the World Health Organization's standard protocol. The Kdr L995F/S alleles were genotyped using Hot Ligation Oligonucleotide Assay. Tested mosquitoes identified using PCR-RFLP were composed of An. arabiensis (68.5%), An. coluzzii (25.5%) and An. gambiae (6%) species. From 2011 to 2015, metabolic resistance increased in Ouro-Housso/Kanadi (up to 89.5% mortality to deltametnrin+synergists in 2015 versus <65% in 2011; p < 0.02), while it decreased in Be-Centre and Bala (>95% mortality in 2011 versus 42–94% in 2015; p < 0.001). Conversely, the Kdr L995F allelic frequencies slightly decreased in Ouro-Housso/Kanadi (from 50% to 46%, p > 0.9), while significantly increasing in Be-Centre and Bala (from 0–13% to 18–36%, p < 0.02). These data revealed two evolutionary trends of deltamethrin resistance mechanisms; non-pyrethroid vector control tools should supplement LLINs in North Cameroon. [ABSTRACT FROM AUTHOR]

Abstract When Tanzanian villages were provided with pyrethroid-treated bednets, bedbugs (Cimicidae) disappeared; however, after about 6 years they have re-appeared in these villages. Using a newly devised test-kit, susceptibility tests of bedbugs Cimex hemipterus (Fabricius) from five of these villages showed that there is resistance to permethrin and alphacypermethrin in bedbugs from each of the villages, in contrast to those from five villages without treated nets. Circumstantial evidence indicates that bedbug resistance to pyrethroid insecticides may evolve more readily in villages with incomplete coverage rates of treated bednets, allowing bedbug infestations to become re-established. Bedbugs have not returned to a village where nearly all the beds have been provided with pyrethroid-treated bednets for 14 years. [ABSTRACT FROM AUTHOR]