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Urbanisation is increasing the risk of mosquito-borne diseases such as dengue and malaria in cities, with resulting impacts on health and development. At the same time, cities worldwide are building and investing in urban resilience. It is not known to what extent and how cities are considering mosquito-borne diseases in their resilience strategies. This research uses a multi-site case study methodology, focused on Resilient Cities Network member cities Chennai (India), Paynesville (Liberia) and Medellín (Colombia), to understand the intersection between mosquito-borne diseases and city resilience. Data collection involved in-depth interviews with resilience representatives of each city and document review to explore perceptions of mosquito-borne diseases, their prioritisation in resilience planning and what resilience activities are implemented and how. Analysis showed that while mosquito-borne diseases are not considered explicitly as a resilience challenge, many resilience activities implemented by cities have co-benefits for mosquito-borne disease control or could be enhanced to realise this potential. For Resilient Cities Network member cities looking to integrate mosquito-borne disease control into their resilience approach, we recommend increasing awareness of interlinkages between city resilience and mosquito-borne diseases, leveraging multi-sectoral collaborations with co-benefits for mosquito-borne disease control, and engaging communities in urban planning and mosquito-borne diseases control efforts.

Rural houses in sub-Saharan Africa are typically hot and allow malaria mosquitoes inside. We assessed whether passive or active ventilation can reduce house entry of malaria mosquitoes and cool a bedroom at night in rural Gambia. Two identical experimental houses were used: one ventilated and one unventilated (control). We evaluated the impact of (i) passive ventilation (solar chimney) and (ii) active ventilation (ceiling fan) on the number of mosquitoes collected indoors and environmental parameters (temperature, humidity, CO 2 , evaporation). Although the solar chimney did not reduce entry of Anopheles gambiae sensu lato , the ceiling fan reduced house entry by 91% compared with the control house. There were no differences in indoor nightly temperature, humidity or CO 2 between intervention and control houses in either experiment. The solar chimney did not improve human comfort assessed using psychrometric analysis. While the ceiling fan improved human comfort pre-midnight, in the morning it was too cool compared with the control house, although this could be remedied through provision of blankets. Further improvements to the design of the solar chimney are needed. High air velocity in the ceiling fan house probably reduced mosquito house entry by preventing mosquito flight. Improved ventilation in houses may reduce malaria transmission.

Mosquito-transmitted diseases are a major threat to health in sub-Saharan Africa, but could be reduced through modifications to the built environment. Here we report findings from a major workshop held to identify the research gaps in this area, namely: (1) evidence of the health benefits to changes to the built environment, (2) understanding how mosquitoes enter buildings, (3) novel methods for reducing mosquito-house entry, (4) sustainable approaches for reducing mosquito habitats, (5) case studies of micro-financing for healthy homes and (6) methods for increasing scale-up. Multidisciplinary research is essential to build out mosquito-transmitted diseases, and not build them in.

Background Malaria in pregnancy remains a public health problem in sub-Saharan Africa. Identifying risk factors for malaria in pregnancy could assist in developing interventions to reduce the risk of malaria in Burkina Faso and other countries in the region. Methods Two cross-sectional surveys were carried out to measure Plasmodium falciparum infection using microscopy in pregnant women in Saponé Health District, central Burkina Faso. Data were collected on individual, household and environmental variables and their association with P. falciparum infection assessed using multivariable analysis. Results A total of 356 pregnant women were enrolled in the surveys, 174 during the dry season and 182 during the wet season. The mean number of doses of sulfadoxine–pyrimethamine for Intermittent Preventive Treatment in pregnancy (IPTp-SP) was 0.4 doses during the first trimester, 1.1 doses at the second and 2.3 doses at the third. Overall prevalence of P. falciparum infection by microscopy was 15.7%; 17.8% in the dry season and 13.7% in the wet season. 88.2% of pregnant women reported sleeping under an insecticide-treated net (ITN) on the previous night. The odds of P. falciparum infection was 65% lower in women who reported using an ITN compared to those that did not use an ITN (Odds ratio, OR = 0.35, 95% CI 0.14–0.86, p = 0.02). IPTp-SP was also associated with reduced P. falciparum infection, with each additional dose of IPTp-SP reducing the odds of infection by 44% (OR = 0.56, 95% CI 0.39–0.79, p = 0.001). Literate women had a 2.54 times higher odds of P. falciparum infection compared to illiterate women (95% CI 1.31–4.91, p = 0.006). Conclusions The prevalence of P. falciparum infection among pregnant women remains high in Burkina Faso, although use of IPTp-SP and ITNs were found to reduce the odds of infection. Despite this, compliance with IPTp-SP remains far from that recommended by the National Malaria Control Programme and World Health Organization. Behaviour change communication should be strengthened to encourage compliance with protective malaria control tools during pregnancy.

In The Gambia, metal-roof houses were hotter during the day than thatched-roof houses. After 24 h, the mortality of Anopheles gambiae, the principal African malaria vector, was 38% higher in metal-roof houses than thatched ones. During the day, mosquitoes in metal-roof houses moved from the hot roof to cooler places near the floor, where the temperature was still high, reaching 35 °C. In laboratory studies, at 35 °C few mosquitoes survived 10 days, the minimum period required for malaria parasite development. Analysis of epidemiological data showed there was less malaria and lower vector survival rates in Gambian villages with a higher proportion of metal roofs. Our findings are consistent with the hypothesis that the indoor climate of metal-roof houses, with higher temperatures and lower humidity, reduces survivorship of indoor-resting mosquitoes and may have contributed to the observed reduction in malaria burden in parts of sub-Saharan Africa.

In sub-Saharan Africa, cooler houses would increase the coverage of insecticide-treated bednets, the primary malaria control tool. We examined whether improved ventilation, using windows screened with netting, cools houses at night and reduces malaria mosquito house entry in The Gambia. Identical houses were constructed, with badly fitting doors the only mosquito entry points. Two men slept in each house and mosquitoes captured using light traps. First, temperature and mosquito density were compared in four houses with 0, 1, 2 and 3 screened windows. Second, carbon dioxide (CO2), a major mosquito attractant, was measured in houses with (i) no windows, (ii) screened windows and (iii) screened windows and screened doors. Computational fluid dynamic modelling captured the spatial movement of CO2. Increasing ventilation made houses cooler, more comfortable and reduced malaria mosquito house entry; with three windows reducing mosquito densities by 95% (95%CI = 90–98%). Screened windows and doors reduced the indoor temperature by 0.6°C (95%CI = 0.5–0.7°C), indoor CO2concentrations by 31% between 21.00 and 00.00 h and malaria mosquito entry by 76% (95%CI = 69–82%). Modelling shows screening reduces CO2plumes from houses. Under our experimental conditions, cross-ventilation not only reduced indoor temperature, but reduced the density of house-entering malaria mosquitoes, by weakening CO2plumes emanating from houses.

Background: Malaria in pregnancy remains a public health problem in sub-Saharan Africa. Identifying risk factors for malaria in pregnancy could assist in developing interventions to reduce the risk of malaria in Burkina Faso and other countries in the region.Methodology: Two cross-sectional surveys were carried out to measure Plasmodium falciparum infection using microscopy in pregnant women in Saponé Health District, central Burkina Faso. Data were collected on individual, household and environmental variables and their association with P. falciparum infection assessed using multivariate analysis. Results: A total of 356 pregnant women were enrolled in the surveys, 174 during the dry season and 182 during the wet season. The mean number of doses of sulphadoxine pyrimethamine for Intermittent Preventive Treatment in pregnancy (IPTp-SP) was 0.4 doses during the first trimester, 1.1 doses at the second and 2.3 doses at the third. Overall prevalence of P. falciparum infection by microscopy was 15.7%; 17.8% in the dry season and 13.7% in the wet season. 88.2% of pregnant women reported sleeping under an insecticide-treated net on the previous night. P. falciparum infection risk in pregnancy was reduced in those women who reported using an ITN (Odds ratio, OR=0.31, 95% CI 0.12-0.79, p=0.02) and an increasing number of IPTp-SP doses during pregnancy, with each additional dose reducing the odds by 40% (OR=0.59, 95% CI 0.43–0.81, pP. falciparum infection among pregnant women remains high in Burkina Faso although use of IPTp-SP and ITNs were found to reduce the odds of infection. Despite this, compliance with IPTp remains far from that recommended by the National Malaria Control Programme and World Health Organization. Behaviour change communication should be improved to encourage compliance with protective malaria control tools during pregnancy.

Summary box Biomedical interventions, such as therapeutics, vaccines and insecticides, are alone insufficient to achieve Sustainable Development Goal (SDG) 3—healthy lives and well-being for all ages. We also need development interventions to tackle the underlying determinants of ill-health by reducing deprivation and improving living conditions and the environment. This recognition formed the bedrock of early public health, from housing improvements and clean water provision in 19th century Europe and North America,1 to house screening for malaria elimination in the USA and water management for historical vector control in Italy, Sri Lanka, Panama and Zambia.2 Today, development interventions are a basic human right and ever more critical in response to rapid population growth, urbanisation and climate change. Despite their importance, many development interventions remain neglected in global health policy. For example, the World Health Organization (WHO) recognises the need for multisectoral approaches to malaria,3 but based on current evidence is unlikely to be able to make a strong …

In sub-Saharan Africa, most transmission of mosquito-transmitted diseases, such as malaria or dengue, occurs within or around houses. Preventing mosquito house entry and reducing mosquito production around the home would help reduce the transmission of these diseases. Based on recent research, we make key recommendations for reducing the threat of mosquito-transmitted diseases through changes to the built environment. The mnemonic, DELIVER , recommends the following best practices: (i) D oors should be screened, self-closing and without surrounding gaps; (ii) E aves, the space between the wall and roof, should be closed or screened; (iii) houses should be L ifted above the ground; (iv) I nsecticide-treated nets should be used when sleeping in houses at night; (v) houses should be V entilated, with at least two large-screened windows to facilitate airflow; (vi) E nvironmental management should be conducted regularly inside and around the home; and (vii) R oofs should be solid, rather than thatch. DELIVER is a package of interventions to be used in combination for maximum impact. Simple changes to the built environment will reduce exposure to mosquito-transmitted diseases and help keep regions free from these diseases after elimination. This article is part of the theme issue ‘Novel control strategies for mosquito-borne diseases'.

Contains fulltext : 232012.pdf (Publisher’s version ) (Open Access) Anopheles stephensi mosquitoes, efficient vectors in parts of Asia and Africa, were found in 75.3% of water sources surveyed and contributed to 80.9% of wild-caught Anopheles mosquitoes in Awash Sebat Kilo, Ethiopia. High susceptibility of these mosquitoes to Plasmodium falciparum and vivax infection presents a challenge for malaria control in the Horn of Africa.

Background: Progress in controlling malaria has stalled in recent years. Today the malaria burden is increasingly concentrated in a few countries, including Burkina Faso, where malaria is not declining. We carried out a cohort study to identify risk factors for malaria infection in children in south-west Burkina Faso, an area with high insecticide-treated net (ITN) coverage and insecticide-resistant vectors.Methods: Incidence of malaria infection was measured in 252 children aged 5 to 15 years, using active and passive detection, during the 2017 transmission season, following clearance of infection. Demographic, socioeconomic, environmental and entomological risk factors, including use of ITNs and insecticide resistance were monitored. Results: During the six-month follow-up period, the overall incidence of Plasmodium falciparum infection, was 2.78 episodes per child (95% CI= 2.66-2.91) by microscopy, and 3.11 (95% CI= 2.95-3.28) by PCR. The entomological inoculation rate (EIR) was 80.4 infective bites per child over the six-month malaria transmission season. At baseline, 80.6% of children were reported as sleeping under an ITN the previous night, although at the last survey, 23.3% of nets were in poor condition and considered no longer protective. No association was found between the rate of P. falciparum infection and either EIR (Incidence Rate Ratio, IRR: 1.00, 95% CI: 1.00–1.00, p=0.08) or mortality in WHO tube tests when vectors were exposed to 0.05% deltamethrin (IRR: 1.05, 95% CI: 0.73–1.50, p=0.79). Travel history (IRR: 1.52, 95% CI: 1.45–1.59, pP. falciparum infection (IRR: 1.05, 95% CI: 1.00–1.11, p=0.04).Conclusions: Malaria infection incidence remains overwhelmingly high in the study area. Our findings suggest that because of the exceptionally high levels of malaria transmission in the study area, malaria elimination cannot be achieved solely by mass deployment of ITNs and additional control measures are needed.

BackgroundTo describe whether SARS-CoV-2 viral loads (VLs) and cycle thresholds (CTs) vary by sample type, disease severity and symptoms duration.MethodsSystematic searches were conducted in MEDLINE, EMBASE, BioRxiv and MedRxiv. Studies reporting individual SARS-CoV-2 VLs and/or CT values from biological samples. Paired reviewers independently screened potentially eligible articles. CT values and VLs distributions were described by sample type, disease severity and time from symptom onset. Differences between groups were examined using Kruskal-Wallis and Dunn ‘s tests (post-hoc test). The risk of bias was assessed using the Joanna Briggs Critical Appraisal Tools.Results14 studies reported CT values, 8 VLs and 2 CTs and VLs, resulting in 432 VL and 873 CT data points. VLs were higher in saliva and sputum (medians 4.7×108 and 6.5×104 genomes per ml, respectively) than in nasopharyngeal and oropharyngeal swabs (medians 1.7×102 and 4.8×103). Combined naso/oropharyngeal swabs had lower CT values (i.e. higher VLs) than single site samples (p=ConclusionVLs are higher in saliva and sputum and in individuals who are asymptomatic of with severe COVID-19. Diagnostic testing strategies should consider that VLs vary by sample type, disease severity and time since symptoms onset.SummaryThis systematic review found a higher viral load in saliva and sputum than in nasopharyngeal swabs, in asymptomatic individuals and patients with severe COVID-19. Diagnostic testing strategies should consider the type of sample, disease severity and the time since symptoms onset.

Vector-borne diseases are a major cause of morbidity and mortality worldwide. Aedes-borne diseases, in particular, including dengue, chikungunya, yellow fever, and Zika, are increasing at an alarming rate due to urbanisation, population movement, weak vector control programmes, and climate change. The World Health Organization calls for strengthening of vector control programmes in line with the Global Vector Control Response (GVCR) strategy, and many vector control programmes are transitioning to this new approach. The Singapore dengue control programme, situated within the country’s larger vision of a clean, green, and sustainable environment for the health and well-being of its citizens, provides an excellent example of the GVCR approach in action. Since establishing vector control operations in the 1960s, the Singapore dengue control programme succeeded in reducing the dengue force of infection 10-fold by the 1990s and has maintained it at low levels ever since. Key to this success is consideration of dengue as an environmental disease, with a strong focus on source reduction and other environmental management methods as the dominant vector control strategy. The programme collaborates closely with other government ministries, as well as town councils, communities, the private sector, and academic and research institutions. Community engagement programmes encourage source reduction, and house-to-house inspections accompanied by a strong legislative framework with monetary penalties help to support compliance. Strong vector and epidemiological surveillance means that routine control activities can be heightened to specifically target dengue clusters. Despite its success, the programme continues to innovate to tackle challenges such as climate change, low herd immunity, and manpower constraints. Initiatives include development of novel vector controls such as Wolbachia-infected males and spatiotemporal models for dengue risk assessment. Lessons learnt from the Singapore programme can be applied to other settings, even those less well-resourced than Singapore, for more effective vector control., Author summary Infections due to dengue and other viruses transmitted by Aedes mosquitoes are on the rise worldwide as a result of urbanisation, trade, population movement, and climate change. Contemporary vector control programmes have struggled to control Aedes-borne diseases, but the Singapore dengue control programme provides a success story. Key to the success is consideration of dengue as an environmental disease, with a corresponding focus on removal of water containers from in and around homes, solid waste management, and limited use of insecticides. The programme relies on close collaboration with other government and nongovernment actors including communities. Community engagement campaigns to ensure high awareness are supported by house-to-house inspections for mosquito habitats and a legislative framework including penalties for noncompliance. The Singapore dengue control programme provides important lessons that can be applied to other Aedes control programmes and vector control programmes more widely.

Mosquitoes are important vectors for pathogens that infect humans and other vertebrate animals. Some aspects of adult mosquito behavior and mosquito ecology play an important role in determining the capacity of vector populations to transmit pathogens. Here, we re-examine factors affecting the transmission of pathogens by mosquitoes using a new approach. Unlike most previous models, this framework considers the behavioral states and state transitions of adult mosquitoes through a sequence of activity bouts. We developed a new framework for individual-based simulation models called MBITES (Mosquito Bout-based and Individual-based Transmission Ecology Simulator). In MBITES, it is possible to build models that simulate the behavior and ecology of adult mosquitoes in exquisite detail on complex resource landscapes generated by spatial point processes. We also developed an ordinary differential equation model which is the Kolmogorov forward equations for models developed in MBITES under a specific set of simplifying assumptions. While mosquito infection and pathogen development are one possible part of a mosquito’s state, that is not our main focus. Using extensive simulation using some models developed in MBITES, we show that vectorial capacity can be understood as an emergent property of simple behavioral algorithms interacting with complex resource landscapes, and that relative density or sparsity of resources and the need to search can have profound consequences for mosquito populations’ capacity to transmit pathogens., Author summary Mathematical modelling of pathogen transmission by mosquitoes began over a century ago with Ronald Ross and has produced a set of metrics that are the basis of measuring transmission. One crucial metric is vectorial capacity (VC), a simple equation describing the potential of mosquitoes to transmit pathogens. Despite its elegance, this formula lacks specificity to describe mosquitoes in a particular landscape. To study how these metrics arise in particular places, we built MBITES (Mosquito Bout-based and Individual-based Transmission Ecology Simulator), a complex stochastic individual-based model where mosquitoes fly from place to place to blood feed, sugar feed, lay eggs, mate, or rest. We also built a related model, MBDETES based on deterministic mathematics to show how the complex behaviors possible in MBITES can be summarized on average, and to provide a bridge to the simple equations describing VC. Through a series of computational experiments, we show a strong dependence VC and other metrics on fine details of the landscape mosquitoes inhabit which are not obvious from simple equations.

Anopheles stephensi, an efficient Asian malaria vector, recently spread into the Horn of Africa and may increase malaria receptivity in African urban areas. We assessed occurrence, genetic complexity, blood meal source and infection status of An. stephensi in Awash Sebat Kilo town, Ethiopia. We used membrane feeding assays to assess competence of local An. stephensi to P. vivax and P. falciparum isolates from clinical patients. 75.3% of the examined waterbodies were infested with An. stephensi developmental stages that were genetically closely related to isolates from Djibouti and Pakistan. Both P. vivax and P. falciparum were detected in wild-caught adult An. stephensi. Local An. stephensi was more receptive to P. vivax compared to a colony of An. arabiensis. We conclude that An. stephensi is an established vector in this part of Ethiopia, highly permissive for local P. vivax and P. falciparum isolates and presents an important new challenge for malaria control.Summary of the articleAn. stephensi, a metropolitan malaria vector that recently expanded to the Horn of African, was highly susceptible to local P. falciparum and P. vivax isolates from Ethiopia and may increase malariogenic potential of rapidly expanding urban settings in Africa.

Background Progress in controlling malaria has stalled in recent years. Today the malaria burden is increasingly concentrated in a few countries, including Burkina Faso, where malaria is not declining. A cohort study was conducted to identify risk factors for malaria infection in children in southwest Burkina Faso, an area with high insecticide-treated net (ITN) coverage and insecticide-resistant vectors. Methods Incidence of Plasmodium falciparum infection was measured in 252 children aged 5 to 15 years, using active and passive detection, during the 2017 transmission season, following clearance of infection. Demographic, socio-economic, environmental, and entomological risk factors, including use of ITNs and insecticide resistance were monitored. Results During the six-month follow-up period, the overall incidence of P. falciparum infection was 2.78 episodes per child (95% CI = 2.66–2.91) by microscopy, and 3.11 (95% CI = 2.95–3.28) by polymerase chain reaction (PCR). The entomological inoculation rate (EIR) was 80.4 infective bites per child over the six-month malaria transmission season. At baseline, 80.6% of children were reported as sleeping under an ITN the previous night, although at the last survey, 23.3% of nets were in poor condition and considered no longer protective. No association was found between the rate of P. falciparum infection and either EIR (incidence rate ratio (IRR): 1.00, 95% CI: 1.00–1.00, p = 0.08) or mortality in WHO tube tests when vectors were exposed to 0.05% deltamethrin (IRR: 1.05, 95% CI: 0.73–1.50, p = 0.79). Travel history (IRR: 1.52, 95% CI: 1.45–1.59, p P. falciparum infection (IRR: 1.05, 95% CI: 1.00–1.11, p = 0.04). Conclusions Incidence of P. falciparum infection remains overwhelmingly high in the study area. The study findings suggest that because of the exceptionally high levels of malaria transmission in the study area, malaria elimination cannot be achieved solely by mass deployment of ITNs and additional control measures are needed.

Vector-borne diseases (VBDs) such as malaria, dengue, and leishmaniasis exert a huge burden of morbidity and mortality worldwide, particularly affecting the poorest of the poor. The principal method by which these diseases are controlled is through vector control, which has a long and distinguished history. Vector control, to a greater extent than drugs or vaccines, has been responsible for shrinking the map of many VBDs. Here, we describe the history of vector control programmes worldwide from the late 1800s to date. Pre 1940, vector control relied on a thorough understanding of vector ecology and epidemiology, and implementation of environmental management tailored to the ecology and behaviour of local vector species. This complex understanding was replaced by a simplified dependency on a handful of insecticide-based tools, particularly for malaria control, without an adequate understanding of entomology and epidemiology and without proper monitoring and evaluation. With the rising threat from insecticide-resistant vectors, global environmental change, and the need to incorporate more vector control interventions to eliminate these diseases, we advocate for continued investment in evidence-based vector control. There is a need to return to vector control approaches based on a thorough knowledge of the determinants of pathogen transmission, which utilise a range of insecticide and non–insecticide-based approaches in a locally tailored manner for more effective and sustainable vector control., Author summary Vector-borne diseases (VBDs) such as dengue, Chagas disease, human African trypanosomiasis (HAT), leishmaniasis, and malaria exert a huge burden of morbidity and mortality worldwide. The principal method by which these diseases are controlled is through vector control. The authors chart the history of vector control through time from elucidation of the transmission route of VBDs to the present day. Pre-1940 vector control relied heavily on environmental management and larval control based on a thorough understanding of pathogen transmission but was replaced by insecticide-based vector control, often deployed as a monotherapy. The authors call for increased political will and investment in vector control and a return to locally tailored vector control that draws on the entire toolbox of interventions available.

On 21 April 1983 the Royal Society of Tropical Medicine and Hygiene held a joint meeting with the Institute of Civil Engineers at Manson House on ‘Engineering against Insect-borne Diseases in the Domestic Environment’. The summary of a talk by Chris Schofield and Graham White on ‘House design and domestic vectors of disease’ was published in a special issue of the Transactions of the Royal Society of Tropical Medicine and Hygiene.1 The manuscript highlights the home and peri-domestic environment as an important site of transmission for many vector-borne diseases, due to the presence of people, and in some cases animals, on which to feed, and provision of shelter from predators and extreme climate. For example, malaria mosquito vectors such as Anopheles gambiae readily enter houses at night to feed on humans. Aedes aegypti, the mosquito vector of diseases including dengue, yellow fever, Zika and chikungunya, is common in urban areas where water that collects in discarded plastic containers, car tires and water storage containers provides ideal aquatic habitats for this mosquito to lay its eggs. Cracked and uneven floors and walls can provide habitats for flea larvae, house dust mites, sandflies and triatomine bugs; the latter are vectors of leishmaniasis and Chagas disease, respectively. Flooded pit latrines, cracked septic tanks and stormwater drains provide habitats for Culex mosquitoes, which can transmit filariasis and contribute to nuisance biting.

Background Larviciding refers to the regular application of chemical or microbial insecticides to water bodies or water containers to kill the aquatic immature forms of the mosquito (the larvae and pupae). Objectives To summarize research evidence evaluating whether larviciding with chemical or microbial insecticides prevents malaria transmission. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library; MEDLINE; Embase; CAB Abstracts; LILACS; the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP); ClinicalTrials.gov; and the ISRCTN registry up to 6 June 2019. Selection criteria We included cluster‐randomized controlled trials (cRCTs), interrupted time series (ITS), randomized cross‐over studies, non‐randomized cross‐over studies, and controlled before‐and‐after studies (CBAs) that compared larviciding with no larviciding. Data collection and analysis We independently assessed trials for eligibility and risk of bias, and extracted data. We assessed the certainty of evidence using the GRADE approach. Main results Four studies (one cRCT, two CBAs, and one non‐randomized cross‐over design) met the inclusion criteria. All used ground application of larvicides (people hand‐delivering larvicides); one evaluated chemical and three evaluated microbial agents. Studies were carried out in The Gambia, Tanzania, Kenya, and Sri Lanka. Three studies were conducted in areas where mosquito aquatic habitats were less extensive (< 1 km²), and one where habitats were more extensive (> 1 km²; a cross‐over study from The Gambia). For aquatic habitats of less than 1 km², one cRCT randomized eight villages in Sri Lanka to evaluate chemical larviciding using insect growth regulator; and two CBA studies undertaken in Kenya and Tanzania evaluated microbial larvicides. In the cRCT, larviciding across all villages was associated with lower malaria incidence (rate ratio 0.24, 4649 participants, low‐certainty evidence) and parasite prevalence (risk ratio (RR) 0.26, 5897 participants, low‐certainty evidence) compared to no larviciding. The two CBA studies reported lower malaria prevalence during the intervention period (parasite prevalence RR 0.79, 95% confidence interval (CI) 0.71 to 0.89; 70,902 participants; low‐certainty evidence). The Kenyan study also reported a reduction in the incidence of new malaria cases (RR 0.62, 95% CI 0.38 to 1.01; 720 participants; very low‐certainty evidence). For aquatic habitats of more than 1 km², the non‐randomized cross‐over trial using microbial larvicides did not detect an effect for malaria incidence (RR 1.58, 95% CI 0.94 to 2.65; 4226 participants), or parasite prevalence (RR 1.15, 95% CI 0.41 to 3.20; 3547 participants); both were very low‐certainty evidence. The Gambia trial also reported the mean haemoglobin level, and there was no difference across the four comparisons (mean difference –0.13, 95% CI –0.40 to 0.13; 3586 participants). We were unable to summarize or pool entomological outcomes due to unreported and missing data. Authors' conclusions Most controlled studies on larviciding have been performed with microbial agents. Ground larviciding for non‐extensive larval habitats may have an effect on malaria transmission, and we do not know if there is an effect in large‐scale aquatic habitats. We found no studies using larviciding application techniques that could cover large aquatic habitats, such as aerial spraying using aircraft., Larviciding to control malaria What was the aim of this review? Larviciding is the regular application of microbial or chemical insecticides to water bodies or water containers. The aim of larviciding is to reduce the adult population of mosquitoes by killing the aquatic immature forms, so that fewer will develop into adults. This should reduce the number of mosquitoes that bite and infect humans with malaria. Key messages All four studies included in this review distributed larvicides manually. Hand larviciding of small mosquito habitats may be effective in preventing malaria. Only one study was conducted in an area where larval habitats spanned a large area and this study found no effect of larviciding. What was studied in the review? We searched for trials that evaluated the impact of larviciding, using a microbial agent or chemical insecticide on malaria transmission. We considered effects on both human health outcomes and on mosquito populations. What were the main results of the review? Evidence from three studies shows that larviciding may decrease at least one malaria disease outcome in some studies, and this was in areas where the mosquito aquatic habitats were less than 1 km2 (low‐certainty evidence). We do not know if larviciding in large water bodies shows an impact on malaria based on results from one study in The Gambia (very low‐certainty evidence). How up to date is the review? We searched for relevant trials up to 6 June 2019.

Background Diseases caused by Aedes-borne viruses, such as dengue, Zika, chikungunya, and yellow fever, are emerging and reemerging globally. The causes are multifactorial and include global trade, international travel, urbanisation, water storage practices, lack of resources for intervention, and an inadequate evidence base for the public health impact of Aedes control tools. National authorities need comprehensive evidence-based guidance on how and when to implement Aedes control measures tailored to local entomological and epidemiological conditions. Methods and findings This review is one of a series being conducted by the Worldwide Insecticide resistance Network (WIN). It describes a framework for implementing Integrated Aedes Management (IAM) to improve control of diseases caused by Aedes-borne viruses based on available evidence. IAM consists of a portfolio of operational actions and priorities for the control of Aedes-borne viruses that are tailored to different epidemiological and entomological risk scenarios. The framework has 4 activity pillars: (i) integrated vector and disease surveillance, (ii) vector control, (iii) community mobilisation, and (iv) intra- and intersectoral collaboration as well as 4 supporting activities: (i) capacity building, (ii) research, (iii) advocacy, and (iv) policies and laws. Conclusions IAM supports implementation of the World Health Organisation Global Vector Control Response (WHO GVCR) and provides a comprehensive framework for health authorities to devise and deliver sustainable, effective, integrated, community-based, locally adapted vector control strategies in order to reduce the burden of Aedes-transmitted arboviruses. The success of IAM requires strong commitment and leadership from governments to maintain proactive disease prevention programs and preparedness for rapid responses to outbreaks., Author summary Aedes aegypti and A. albopictus are mosquito species that thrive in towns and cities and can transmit viruses to humans that cause diseases, such as dengue, Zika, chikungunya, and yellow fever. The geographic range of human infection with these viruses is rapidly expanding globally. Even when preventative or therapeutic treatments are available to fight these diseases, controlling the mosquito vector will remain an important control option. We therefore developed a framework called IAM that offers decision-making guidance based on available evidence of effective control of Aedes at different levels of infestation and virus transmission risk. Our work aims to strengthen the capacity of countries at risk of and/or affected by these diseases and vectors so they will be better prepared for existing and emerging Aedes-borne disease threats.

Summary Introduction Unprecedented improvements in housing are occurring across much of rural sub-Saharan Africa, but the consequences of these changes on malaria transmission remain poorly explored. We examined how different typologies of rural housing affect mosquito house entry and indoor climate. Methods Five typologies of mud-block houses were constructed in rural Gambia: four were traditional designs with poorly fitted doors and one was a novel design with gable windows to improve ventilation. In each house, one male volunteer slept under a bednet and mosquitoes were collected indoors with a light trap. Typologies were rotated between houses weekly. Indoor conditions were monitored with data loggers and the perceived comfort of sleepers recorded with questionnaires. We used pyschrometric modelling to quantify the comfort of the indoor climate using the logger data. Primary measurements were mean number of Anopheles gambiae and mean temperature for each house typology. Findings In thatched-roofed houses, closing the eaves reduced A gambiae house entry by 94% (95% CI 89–97) but increased the temperature compared with thatched-roofed houses with open eaves. In houses with closed eaves, those with metal roofs had more A gambiae, were hotter (1·5°C hotter [95% CI 1·3–1·7]) between 2100h and 2300 h, and had 25% higher concentrations of carbon dioxide (211·1 ppm higher [117·8–304·6]) than those with thatched roofs. In metal-roofed houses with closed eaves, mosquito house entry was reduced by 96% (91–98) by well fitted screened doors. Improved ventilation of metal-roofed houses made them as cool as thatched houses with open eaves. Metal-roofed houses with closed eaves were considered more uncomfortable than thatched ones with closed eaves. In metal-roofed houses, ventilated houses were more comfortable than unventilated houses before midnight, when people retired to bed. Interpretation Closing the eaves reduced vector entry in thatched houses but increased entry in metal-roofed houses. Metal-roofed houses with closed eaves were, however, protected against malaria vectors by well fitted screened doors and were made comfortable by increasing ventilation. House designs that exclude mosquitoes and are comfortable to live in should be a priority in sub-Saharan Africa. Funding Sir Halley Stewart Trust, Global Clinical Trials, and Global Challenges Research Fund.

Background Insecticide resistance threatens malaria control in sub-Saharan Africa. Knockdown resistance to pyrethroids and organochlorines in Anopheles gambiae sensu lato (s.l.) is commonly caused by mutations in the gene encoding a voltage-gated sodium channel which is the target site for the insecticide. The study aimed to examine risk factors for knockdown resistance in An. gambiae s.l. and its relationship with malaria infection in children in rural Gambia. Point mutations at the Vgsc-1014 locus, were measured in An. gambiae s.l. during a 2-year trial. Cross-sectional surveys were conducted at the end of the transmission season to measure malaria infection in children aged 6 months–14 years. Results Whilst few Anopheles arabiensis and Anopheles coluzzii had Vgsc-1014 mutations, the proportion of An. gambiae sensu stricto (s.s.) mosquitoes homozygous for the Vgsc-1014F mutation increased from 64.8 to 90.9% during the study. The Vgsc-1014S or 1014F mutation was 80% higher in 2011 compared to 2010, and 27% higher in the villages with indoor residual spraying compared to those without. An increase in the proportion of An. gambiae s.l. mosquitoes with homozygous Vgsc-1014F mutations and an increase in the proportion of An. gambiae s.s. in a cluster were each associated with increased childhood malaria infection. Homozygous Vgsc-1014F mutations were, however, most common in An. gambiae s.s. and almost reached saturation during the study meaning that the two variables were colinear. Conclusions As a result of colinearity between homozygous Vgsc-1014F mutations and An. gambiae s.s., it was not possible to determine whether insecticide resistance or species composition increased the risk of childhood malaria infection. Electronic supplementary material The online version of this article (10.1186/s12936-018-2348-8) contains supplementary material, which is available to authorized users.

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:\ud \ud To evaluate whether larviciding controls malaria transmission.

Scientific Data 4:170050 doi: 10.1038/sdata.2017.50 (2017); Published 11 April 2017; Updated 30 May 2017 The financial support for this Data Descriptor was not fully acknowledged. The Acknowledgements should have included the following: S.I.H. is funded by a Senior Research Fellowship from the Wellcome Trust [095066].

The vector Aedes aegypti is now present in nearly every tropical and sub-tropical region in the world and poses a threat to health globally. The mosquito can transmit several viruses that cause diseases, such as dengue fever, chikungunya, yellow fever and Zika virus infection. Recent outbreaks of Ae. aegypti-borne diseases have shown that urban areas are particularly vulnerable because the built environment provides ideal conditions for mosquito proliferation and contact with humans. Unless the global public health community takes a coordinated, pre-emptive approach to controlling the Ae. aegypti population, these outbreaks will become more common and widespread as urban populations expand and movement of people and their goods increase. Improving the built environment would contribute to a long-term solution to reducing the threat of Ae. aegypti-bome diseases. Our ability to deal with Ae. Aegypti-borne viral epidemics is limited. Apart from supportive care, specific treatments for vector-borne viral diseases are lacking. No commercial vaccines for Zika or chikungunya are available, the only licensed dengue vaccine is partially protective (1) and globally the yellow fever vaccine is in short supply. (2) Although current vector control programmes are often poorly resourced and under-used, (3) historically, vector control was the main method for controlling mosquito-borne diseases. By using container inspections, oiling of breeding sites and later perifocal spraying of DDT (dichlorodiphenyltrichloroethane) in water containers and on nearby walls, Ae. aegypti, yellow fever and dengue fever were successfully eliminated from much of South America in the 1960s. (4) In the 1970s and 1980s in Singapore and in the 1980s and 1990s in Cuba, controlling adult and larval Ae. aegypti reduced dengue transmission. In the future, new methods of vector control, such as novel delivery systems for insecticides with new modes of action and release of Wolbachia-infected or genetically-modified mosquitoes, may contribute to the control or elimination of mosquito-borne diseases. (5) Affected towns and cities, however, already have several options to reduce Ae. aegyptibome diseases and these options should be built into future planning strategies. Current Ae. aegypti control focuses on reducing densities of immature and adult mosquitoes with larvicides or adult insecticides. While these interventions can be effective, continued reliance on these single-intervention control programmes is resource-intensive and threatened by insecticide resistance. The World Health Organization (3,6) and other major international organizations7 have recommended an intersectoral approach to achieve more effective and sustainable vector control. Governments, however, have often overlooked such approaches when designing vector control programmes. An underutilized aspect of integrated vector management is improving the urban built environment to reduce Ae. aegypti populations and their contact with humans. (8) The built environment in many urban areas provides abundant habitats for the immature stages of Ae. aegypti, and high human population densities create the potential for large outbreaks of Aedes-borne diseases. More than half of the world's population currently lives in urban areas and by 2050 it is estimated that 70% of the population will live in cities. (9) This urban expansion will increase the frequency and intensity of Aedes-borne outbreaks. However, developing urban areas that minimize human contact with mosquitoes could enable sustainable and cost-effective prevention of mosquito-borne diseases. Several aspects of urban planning can be targeted to reduce human contact with Ae. aegypti. Reducing the availability of small plastic containers around homes and improving solid waste management will remove habitats for Ae. aegypti larvae development. Provision of constant piped water will reduce the need to store water in containers in and around homes, since water-filled containers are known to be favoured habitats for Ae. …

Unprecedented economic growth in Southeast Asia (SEA) has encouraged the expansion of rubber plantations. This land-use transformation is changing the risk of mosquito-borne diseases. Mature plantations provide ideal habitats for the mosquito vectors of malaria, dengue, and chikungunya. Migrant workers may introduce pathogens into plantation areas, most worryingly artemisinin-resistant malaria parasites. The close proximity of rubber plantations to natural forest also increases the threat from zoonoses, where new vector-borne pathogens spill over from wild animals into humans. There is therefore an urgent need to scale up vector control and access to health care for rubber workers. This requires an intersectoral approach with strong collaboration between the health sector, rubber industry, and local communities.

Vector-borne diseases (VBDs) such as malaria, dengue, and leishmaniasis cause a high level of morbidity and mortality. Although vector control tools can play a major role in controlling and eliminating these diseases, in many cases the evidence base for assessing the efficacy of vector control interventions is limited or not available. Studies assessing the efficacy of vector control interventions are often poorly conducted, which limits the return on investment of research funding. Here we outline the principal design features of Phase III vector control field studies, highlight major failings and strengths of published studies, and provide guidance on improving the design and conduct of vector control studies. We hope that this critical assessment will increase the impetus for more carefully considered and rigorous design of vector control studies.

Introduction Insecticide-treated nets (ITNs) are one of the main interventions used for malaria control. However, these nets may also be effective against other vector borne diseases (VBDs). We conducted a systematic review and meta-analysis to estimate the efficacy of ITNs, insecticide-treated curtains (ITCs) and insecticide-treated house screening (ITS) against Chagas disease, cutaneous and visceral leishmaniasis, dengue, human African trypanosomiasis, Japanese encephalitis, lymphatic filariasis and onchocerciasis. Methods MEDLINE, EMBASE, LILACS and Tropical Disease Bulletin databases were searched using intervention, vector- and disease-specific search terms. Cluster or individually randomised controlled trials, non-randomised trials with pre- and post-intervention data and rotational design studies were included. Analysis assessed the efficacy of ITNs, ITCs or ITS versus no intervention. Meta-analysis of clinical data was performed and percentage reduction in vector density calculated. Results Twenty-one studies were identified which met the inclusion criteria. Meta-analysis of clinical data could only be performed for four cutaneous leishmaniasis studies which together showed a protective efficacy of ITNs of 77% (95%CI: 39%–91%). Studies of ITC and ITS against cutaneous leishmaniasis also reported significant reductions in disease incidence. Single studies reported a high protective efficacy of ITS against dengue and ITNs against Japanese encephalitis. No studies of Chagas disease, human African trypanosomiasis or onchocerciasis were identified. Conclusion There are likely to be considerable collateral benefits of ITN roll out on cutaneous leishmaniasis where this disease is co-endemic with malaria. Due to the low number of studies identified, issues with reporting of entomological outcomes, and few studies reporting clinical outcomes, it is difficult to make strong conclusions on the effect of ITNs, ITCs or ITS on other VBDs and therefore further studies be conducted. Nonetheless, it is clear that insecticide-treated materials such as ITNs have the potential to reduce pathogen transmission and morbidity from VBDs where vectors enter houses., Author Summary Malaria is a deadly disease caused by a parasite which is transmitted by anopheline mosquitoes. Bednets treated with insecticide are one of the key tools used to prevent malaria and they have been distributed on a large scale in many countries, particularly in Africa. It may be possible to control other diseases transmitted by insects using insecticide-treated bednets because many of these insects also enter houses. We did a review of studies looking at the effectiveness of insecticide-treated bednets, curtains and house screening against nine major diseases transmitted by insects. We assessed the effect these tools had on reducing numbers of the insects and disease in humans. Insecticide-treated bednets were found to be effective in preventing cutaneous leishmaniasis—a disease transmitted by sandflies—and insecticide-treated curtains and screening showed potential in preventing other insect borne diseases. Although further studies are required, it is clear that insecticide-treated bednets, curtains and screening have the potential to prevent transmission of insect-transmitted diseases.

Seasonal malaria chemoprevention, previously known as intermittent preventive treatment in children, is highly effective in areas with a short malaria transmission season. Here we assess seasonality in malaria incidence data and define a predictor of seasonality based on rainfall. We then use spatial rainfall, malaria endemicity and population data to identify areas likely to have highly seasonal malaria incidence, and estimate the population at risk and malaria burden in areas where seasonal malaria chemoprevention would be appropriate. We estimate that in areas suitable for seasonal malaria chemoprevention, there are 39 million children under 5 years of age, who experience 33.7 million malaria episodes and 152,000 childhood deaths from malaria each year. The majority of this burden occurs in the Sahelian or sub-Sahelian regions of Africa. Our data suggest that seasonal malaria chemoprevention has the potential to avert several million malaria cases and tens of thousands of childhood deaths each year if successfully delivered to the populations at risk., Seasonal malaria chemoprevention can lower the incidence of malaria in areas where transmission is highly periodical. Combining data on rainfall, population and malaria endemicity, Cairns et al. identify geographical areas in sub-Saharan Africa where this intervention is likely to be effective and cost-effective.

The kingdom of Luba Lomami was enlarged and strengthened by the conquest of Kalala Ilunga at an unknown date before the end of the sixteenth century. It became a large but not dominant state. The expansion of Luba Lomami is generally considered to have occurred in the early eighteenth century, as a delayed consequence of the Kalala Ilunga conquest. In this it is said to have been paralleled by the expansion of Lunda. Unlike Lunda, however, it is supposed to have suffered from severe structural deficiencies. These, it has been argued, inhibited its further expansion and, in the mid-nineteenth century, caused it to disintegrate.It is suggested here, however, that the expansion of Luba Lomami did not occur until the late eighteenth or early nineteenth century. This expansion coincided with the extension of the Bisa trading system into the chiefdoms south-east of Luba Lomami and was designed to capture this trade. Later conquests in the south may have been related to the development of Nyamwezi and Bihe trading systems. However, the principal motive for further expansion was the need to capture new sources of ivory and, to a lesser extent, slave-yielding lands. Luba Lomami's success can be attributed to its proximity to the Bisa trade route, its relatively centralized political structures, the availability of viable areas of expansion, and the existence of suitable mechanisms to incorporate the conquered chiefdoms. In the first half of the nineteenth century Luba Lomami subjected most of the area between the Lubilash and Lake Tanganyika and between the forest and the copper belt.In about 1870 the terms of the long-distance trade turned against Luba Lomami. New traders arrived carrying guns. Luba Lomami could not match the new techniques for it no longer had the resources with which to purchase guns. Its own resources of ivory and slaves were exhausted. It could no longer obtain supplies by expansion, for the traders were carving out new states on its periphery, and it was itself becoming subject to slave raids and encroachment. This external pressure weakened the political structures. Rival brothers sought the aid of mercenary traders to promote their cause. The ideological basis of the state was undermined. In a desperate attempt to obtain guns the emperors began to raid for slaves amongst their own people. The empire disintegrated and, in about 1890, the rump of the state became tributary to the trader-state of Msiri.

Potato plots in southern England were covered by polyethylene sheeting perforated by 9-mm slits that opened to permit expansion as the plants grew. The slits admitted rain and also some aphids. Covered plants received 93% less immigrant aphids than exposed plants. The greatest protection was from Myzus persicae (Sulz.) (99%), whilst noncolonising species were reduced by 77%. It is improbable that the barrier to movement presented by the polyethylene would differentiate between incoming species or that M. persicae, for which potato is a preferred host, would escape more readily once inside the cover. This suggests that the behavioural barrier to alighting is in response to the reflection of high wavelength light at the polyethylene surface which affected M. persicae more than other species. The method has potential in protection of crops from aphids.

Background Recommended vector control tools against malaria, such as long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS), mainly target mosquitoes that rest and feed on human hosts indoors. However, in some malaria-endemic areas, such as Southeast Asia and South America, malaria vectors primarily bite outdoors meaning that LLINs and IRS may be less effective. In these situations the use of topical insect repellents may reduce outdoor biting and morbidity from malaria. A systematic review and meta-analysis was conducted to assess the efficacy of topical insect repellents against malaria. Methods Studies were identified using database searches (MEDLINE, EMBASE, Web of Science and clinical trials registers), as well as reference list searches and contact with researchers. Randomized and non-randomized controlled trials were included that assessed the effect of topical repellents (all active ingredients and concentrations) on Plasmodium falciparum or Plasmodium vivax malaria or infection in malaria-endemic populations. Meta-analysis of clinical data was conducted in order to generate summary risk ratios. Results Ten trials met the inclusion criteria. Studies varied in terms of repellent active ingredient and formulation, co-interventions, study population, compliance, and follow-up period. Topical repellents showed an 18% protective efficacy against P. falciparum malaria, although this was not significant (95% CI: -8%, 38%). Similarly, the average protective efficacy of topical repellents against P. vivax malaria did not reach significance (protective efficacy: 20%, 95% CI: -37%, 53%). Exclusion of non-randomized trials from the meta-analysis did not alter the findings. Conclusions Although topical repellents can provide individual protection against mosquitoes, the results of this meta-analysis indicate that topical repellents are unlikely to provide effective protection against malaria. However, there was substantial heterogeneity between studies included and the relatively small number of studies meant that this heterogeneity could not be fully explored in the analysis. Further well-designed trials of topical repellents at appropriate doses and alternative modes of repellent delivery, such as spatial repellents and long-lasting insecticide-treated clothing, are required. Electronic supplementary material The online version of this article (doi:10.1186/1475-2875-13-446) contains supplementary material, which is available to authorized users.