Citizen science for monitoring the spatial and temporal dynamics of malaria vectors in relation to environmental risk factors in Ruhuha, Rwanda

Abstract Background As part of malaria prevention and control efforts, the distribution and density of malaria mosquitoes requires continuous monitoring. Resources for long-term surveillance of malaria vectors, however, are often limited. The aim of the research was to evaluate the value of citizen science in providing insight into potential malaria vector hotspots and other malaria relevant information, and to determine predictors of malaria vector abundance in a region where routine mosquito monitoring has not been established to support vector surveillance. Methods A 1-year citizen science programme for malaria mosquito surveillance was implemented in five villages of the Ruhuha sector in Bugesera district, Rwanda. In total, 112 volunteer citizens were enrolled and reported monthly data on mosquitoes collected in their peridomestic environment using handmade carbon-dioxide baited traps. Additionally, they reported mosquito nuisance experienced as well as the number of confirmed malaria cases in their household. Results In total, 3793 female mosquitoes were collected, of which 10.8% were anophelines. For the entire period, 16% of the volunteers reported having at least one confirmed malaria case per month, but this varied by village and month. During the study year 66% of the households reported at least one malaria case. From a sector perspective, a higher mosquito and malaria vector abundance was observed in the two villages in the south of the study area. The findings revealed significant positive correlations among nuisance reported and confirmed malaria cases, and also between total number of Culicidae and confirmed malaria cases, but not between the numbers of the malaria vector Anopheles gambiae and malaria cases. At the sector level, of thirteen geographical risk factors considered for inclusion in multiple regression, distance to the river network and elevation played a role in explaining mosquito and malaria mosquito abundance. Conclusions The study demonstrates that a citizen science approach can contribute to mosquito monitoring, and can help to identify areas that, in view of limited resources for control, are at higher risk of malaria.

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Risk Factors Associated With House Entry of Malaria Vectors in an Area of Burkina Faso With High, Persistent Malaria Transmission and High Insecticide Resistance

10.21203/rs.3.rs-273831/v1 ◽

2021 ◽

Author(s):

Jean Baptiste Yaro ◽

Alfred Tiono ◽

Antoine Sanou ◽

Hyacinthe K Toe ◽

John Bradley ◽

...

Keyword(s):

Risk Factors ◽

Insecticide Resistance ◽

Burkina Faso ◽

Malaria Transmission ◽

Malaria Vector ◽

Negative Binomial ◽

Malaria Vectors ◽

Linear Mixed Effect Model ◽

Mixed Effect ◽

Factors Associated

Abstract Background: In rural Burkina Faso, the malaria vector An. gambiae s.l. is primarily thought to feed indoors at night. Identification of factors which influence mosquito house entry could lead to development of novel malaria vector control interventions. A study was therefore carried out to identify risk factors associated with house entry of An. gambiae s.l. in south-west Burkina Faso, an area of high insecticide resistance. Methods: Mosquitoes were sampled monthly during the malaria transmission season using CDC light traps in 252 houses from 10 villages, each house sleeping at least one child aged five to 15 years old. Putative risk factors for house entry of An. gambiae s.l. were measured, including socio-economic status, caregiver’s education and occupation, number of people sleeping in the same room as the child, use of anti-mosquito measures, house construction and fittings, proximity of mosquito aquatic habitats and presence of animals near the house. Mosquito counts were compared using a generalised linear mixed-effect model with negative binomial and log link function, adjusting for repeated collections. Results: 20,929 mosquitoes were caught, of which 16,270 (77.7%) were An. gambiae s.l. Of the 6,691 An. gambiae s.l. identified to species, 4,101 (61.3%) were An. gambiae and 2,590 (38.7%) An. coluzzii. Having an electricity supply (incidence rate ratio, IRR = 0.4, 95% CI = 0.3–0.7, p = 0.001) and a metal-roofed house (IRR, = 0.6, 95% CI = 0.4–1.0, p = 0.034) were associated with fewer malaria vectors inside the home. Conclusion: This study demonstrated that there were fewer An. gambiae s.l. in homes with electricity and a metal roof compared to those that did not. Brightly-lit, well-built houses with metal roofs may reduce entry of malaria mosquitoes compared to dimly-lit, poorly-built thatched roofed houses.

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Assessment of novel Lehmann’s Funnel Entry Trap prototypes performance to control malaria mosquito populations

10.21203/rs.3.rs-33604/v2 ◽

2020 ◽

Author(s):

Roger Sanou ◽

Hamidou Maïga ◽

Etienne M. Bilgo ◽

P. Simon Sawadogo ◽

Bazoumana D. Sow ◽

...

Keyword(s):

Malaria Vector ◽

Large Scale ◽

The Other ◽

Malaria Vectors ◽

Mosquito Density ◽

Malaria Mosquito ◽

Killing Effect ◽

Global Consensus ◽

Community Acceptance ◽

Study Sites

Abstract BackgroundThere is a global consensus that new intervention tools are needed to make the final steps toward malaria elimination/eradication. In a recent study in Burkina Faso, the Lehmann Funnel Entry Trap (LFET) has shown promising results in the reduction of mosquito densities, even in areas where insecticide resistance is as high as 80%. The LFET requires no chemicals and is self-operated. However, one of the issues with the original LFET is the size of the funnel, which often occupies too much space within users’ homes. Here, we compared the performance of three new, smaller-sized LFET prototypes that combine a screening and killing effect on mosquitoes. MethodsThe study was carried out over three months during the rainy season in low and high malaria vector density sites, Soumousso and Vallée du Kou, respectively. The original LFET (or ‘Prototype 1’/’P1’) was modified to produce three new prototypes, which we will refer to as Prototype 2 (‘the Medium’ or ‘P2’), Prototype 3 (P3) and Prototype 4 (P4). Each of the new prototypes was tested on eight days per month over the three-month period to assess their effectiveness in trapping and killing mosquitoes entering houses through the windows compared to the original LFET. ResultsOverall, 78,435 mosquitoes (mainly Anopheles gambiae s.l.) were collected in the two study sites, both in the traps and in the houses. A total of 56,430 (72%) mosquitoes were collected from the traps. In Vallée du Kou, the original LFET caught a greater number of mosquitoes than the Medium (prototype 2), whereas no difference was observed between the other new prototypes (3 and 4) and the Medium. In Soumousso, the original and Medium LFETs both collected significantly greater numbers of mosquitoes compared to prototypes 3 and 4. ConclusionThis study has shown that the new LFET prototypes are effective in trapping mosquitoes in high mosquito density settings. A large-scale study with one of the prototypes will be needed to assess community acceptance of the traps and their ability to control malaria vectors.

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20-Hydroxyecdysone (20E) signaling as a promising target for the chemical control of malaria vectors

Parasites & Vectors ◽

10.1186/s13071-020-04558-5 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Elodie Ekoka ◽

Surina Maharaj ◽

Luisa Nardini ◽

Yael Dahan-Moss ◽

Lizette L. Koekemoer

Keyword(s):

Vector Control ◽

Signaling Pathway ◽

Malaria Vector ◽

Vector Competence ◽

Rapid Development ◽

World Health ◽

Malaria Vectors ◽

Malaria Vector Control ◽

Insect Growth Regulators ◽

Vector Abundance

AbstractWith the rapid development and spread of resistance to insecticides among anopheline malaria vectors, the efficacy of current World Health Organization (WHO)-approved insecticides targeting these vectors is under threat. This has led to the development of novel interventions, including improved and enhanced insecticide formulations with new targets or synergists or with added sterilants and/or antimalarials, among others. To date, several studies in mosquitoes have revealed that the 20-hydroxyecdysone (20E) signaling pathway regulates both vector abundance and competence, two parameters that influence malaria transmission. Therefore, insecticides which target 20E signaling (e.g. methoxyfenozide and halofenozide) may be an asset for malaria vector control. While such insecticides are already commercially available for lepidopteran and coleopteran pests, they still need to be approved by the WHO for malaria vector control programs. Until recently, chemicals targeting 20E signaling were considered to be insect growth regulators, and their effect was mostly studied against immature mosquito stages. However, in the last few years, promising results have been obtained by applying methoxyfenozide or halofenozide (two compounds that boost 20E signaling) to Anopheles populations at different phases of their life-cycle. In addition, preliminary studies suggest that methoxyfenozide resistance is unstable, causing the insects substantial fitness costs, thereby potentially circumventing one of the biggest challenges faced by current vector control efforts. In this review, we first describe the 20E signaling pathway in mosquitoes and then summarize the mechanisms whereby 20E signaling regulates the physiological processes associated with vector competence and vector abundance. Finally, we discuss the potential of using chemicals targeting 20E signaling to control malaria vectors.

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Assessment of novel Lehmann’s funnel entry trap prototypes performance to control malaria mosquito populations

Malaria Journal ◽

10.1186/s12936-020-03532-x ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Roger Sanou ◽

Hamidou Maïga ◽

Etienne M. Bilgo ◽

Simon P. Sawadogo ◽

Bazoumana B. D. Sow ◽

...

Keyword(s):

Malaria Vector ◽

Large Scale ◽

The Other ◽

Malaria Vectors ◽

Mosquito Density ◽

Malaria Mosquito ◽

Killing Effect ◽

Global Consensus ◽

Community Acceptance ◽

Study Sites

Abstract Background There is a global consensus that new intervention tools are needed for the final steps toward malaria elimination/eradication. In a recent study in Burkina Faso, the Lehmann Funnel Entry Trap (LFET) has shown promising results in the reduction of mosquito densities, even in areas where insecticide resistance is as high as 80%. The LFET requires no chemicals and is self-operated. However, one of the issues with the original LFET is the size of the funnel, which often occupies too much space within users’ homes. Here, the performance of three new, smaller-sized LFET prototypes that combine a screening and killing effect on mosquitoes was assessed. Methods The study was carried out over three months during the rainy season in low and high malaria vector density sites, Soumousso and Vallée du Kou, respectively. The original LFET (or ‘Prototype 1’/‘P1’) was modified to produce three new prototypes, which were referred to as prototype 2 (‘the Medium’ or ‘P2’), prototype 3 (P3) and prototype 4 (P4). Each of the new prototypes was tested on eight days per month over the three-month period to assess their effectiveness in trapping and killing mosquitoes entering houses through the windows compared to the original LFET. Results Overall, 78,435 mosquitoes (mainly Anopheles gambiae sensu lato) were collected in the two study sites, both in the traps and in the houses. A total of 56,430 (72%) mosquitoes were collected from the traps. In Vallée du Kou, the original LFET caught a greater number of mosquitoes than the medium (prototype 2), whereas no difference was observed between the other new prototypes (3 and 4) and the medium. In Soumousso, both the original and medium LFETs collected significantly greater numbers of mosquitoes compared to prototypes 3 and 4. Conclusion This study has shown that the new LFET prototypes are effective in trapping mosquitoes in high mosquito density settings. A large-scale study with one of the prototypes will be needed to assess community acceptance of the traps and their ability to control malaria vectors.

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Risk factors associated with house entry of malaria vectors in an area of Burkina Faso with high, persistent malaria transmission and high insecticide resistance

Malaria Journal ◽

10.1186/s12936-021-03926-5 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Jean Baptiste Yaro ◽

Alfred B. Tiono ◽

Antoine Sanou ◽

Hyacinthe K. Toe ◽

John Bradley ◽

...

Keyword(s):

Risk Factors ◽

Insecticide Resistance ◽

Burkina Faso ◽

Malaria Transmission ◽

Malaria Vector ◽

Malaria Vectors ◽

Anopheles Coluzzii ◽

Mixed Effect ◽

Factors Associated ◽

House Construction

Abstract Background In rural Burkina Faso, the primary malaria vector Anopheles gambiae sensu lato (s.l.) primarily feeds indoors at night. Identification of factors which influence mosquito house entry could lead to development of novel malaria vector control interventions. A study was therefore carried out to identify risk factors associated with house entry of An. gambiae s.l. in south-west Burkina Faso, an area of high insecticide resistance. Methods Mosquitoes were sampled monthly during the malaria transmission season using CDC light traps in 252 houses from 10 villages, each house sleeping at least one child aged five to 15 years old. Potential risk factors for house entry of An. gambiae s.l. were measured, including socio-economic status, caregiver’s education and occupation, number of people sleeping in the same part of the house as the child, use of anti-mosquito measures, house construction and fittings, proximity of anopheline aquatic habitats and presence of animals near the house. Mosquito counts were compared using a generalized linear mixed-effect model with negative binomial and log link function, adjusting for repeated collections. Results 20,929 mosquitoes were caught, of which 16,270 (77.7%) were An. gambiae s.l. Of the 6691 An. gambiae s.l. identified to species, 4101 (61.3%) were An. gambiae sensu stricto and 2590 (38.7%) Anopheles coluzzii. Having a metal-roof on the child’s sleeping space (IRR = 0.55, 95% CI 0.32–0.95, p = 0.03) was associated with fewer malaria vectors inside the home. Conclusion This study demonstrated that the rate of An. gambiae s.l. was 45% lower in sleeping spaces with a metal roof, compared to those with thatch roofs. Improvements in house construction, including installation of metal roofs, should be considered in endemic areas of Africa to reduce the burden of malaria.

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Assessment of Novel Lehmann’s Funnel Entry Trap Prototypes Performance to Control Malaria Mosquito Populations

10.21203/rs.3.rs-33604/v1 ◽

2020 ◽

Author(s):

Roger Sanou ◽

Hamidou Maïga ◽

Etienne M. Bilgo ◽

P. Simon Sawadogo ◽

Bazoumana D. Sow ◽

...

Keyword(s):

Vector Control ◽

Malaria Vector ◽

Large Scale ◽

Malaria Vectors ◽

Malaria Vector Control ◽

Malaria Mosquito ◽

Killing Effect ◽

Vector Density ◽

Global Consensus ◽

Community Acceptance

Abstract BackgroundThere is a global consensus that new intervention tools are needed to cross the last miles in malaria elimination/eradication. In a recent study in Burkina Faso, the Lehmann Funnel Entry Trap (LFET) have shown excellent promise in mosquito densities reducing even in area of high insecticide resistance up to 80%. It requires no chemicals and is self-operated. However, one of the issues of the LFET is the big size of the funnel occupying lot of space inside houses. Here we compared the performance of three new prototypes of LFET with reduced size that combine screening and killing effect on mosquitoes. MethodsThe study was carried out for three months during the rainy season both in low and high malaria vector density sites, Soumousso and Vallée du Kou respectively. The original LFET was modified and 3 new prototypes were produced locally and tested over 3 months (8 days/month) to evaluate their effectiveness in trapping and killing mosquitoes entering houses through the windows. ResultsIn both sites, an overall of 78,435 culicine mosquitoes collected in both traps and houses and most of them were mainly Anopheles gambiae s.l. n= 76,558 (98%) and other species represented n = 1,877 (2%). Of the culicine caught in the trial, n= 55,256 (72%) were collected in traps. The 3 new LFET prototypes reduced the indoor density of mosquitoes collected in the houses by a range of 36 to 73% and 69 to 70% in low vector density setting, Soumousso and high vector density area, Vallée du Kou respectively. The prototype 1 caught a greater number of mosquitoes than the prototype 2 whereas no difference was observed between other prototypes in VK3. In Soumousso, the prototypes 1 and 2 collected significantly higher number of mosquitoes compared to the prototypes 3 and 4. ConclusionThis study has shown that the new LFET prototypes are promising for malaria vector control and could enter in the malaria vector control toolbox in the coming years. Therefore, a large-scale study with one of the prototypes is needed on the practical ability and community acceptance of the LFET to control malaria vectors.

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Assessment of novel Lehmann’s funnel entry trap prototypes performance to control malaria mosquito populations

10.21203/rs.3.rs-33604/v4 ◽

2020 ◽

Author(s):

Roger Sanou ◽

Hamidou Maïga ◽

Etienne M. Bilgo ◽

Simon P. Sawadogo ◽

Bazoumana D. Sow ◽

...

Keyword(s):

Malaria Vector ◽

Large Scale ◽

The Other ◽

Malaria Vectors ◽

Mosquito Density ◽

Malaria Mosquito ◽

Killing Effect ◽

Global Consensus ◽

Community Acceptance ◽

Study Sites

Abstract Background There is a global consensus that new intervention tools are needed for the final steps toward malaria elimination/eradication. In a recent study in Burkina Faso, the Lehmann Funnel Entry Trap (LFET) has shown promising results in the reduction of mosquito densities, even in areas where insecticide resistance is as high as 80%. The LFET requires no chemicals and is self-operated. However, one of the issues with the original LFET is the size of the funnel, which often occupies too much space within users’ homes. Here, the performance of three new, smaller-sized LFET prototypes that combine a screening and killing effect on mosquitoes was assessed. Methods The study was carried out over three months during the rainy season in low and high malaria vector density sites, Soumousso and Vallée du Kou, respectively. The original LFET (or ‘Prototype 1’/’P1’) was modified to produce three new prototypes, which were referred to as Prototype 2 (‘the Medium’ or ‘P2’), Prototype 3 (P3) and Prototype 4 (P4). Each of the new prototypes was tested on eight days per month over the three-month period to assess their effectiveness in trapping and killing mosquitoes entering houses through the windows compared to the original LFET. Results Overall, 78,435 mosquitoes (mainly Anopheles gambiae sensu lato) were collected in the two study sites, both in the traps and in the houses. A total of 56,430 (72%) mosquitoes were collected from the traps. In Vallée du Kou, the original LFET caught a greater number of mosquitoes than the Medium (prototype 2), whereas no difference was observed between the other new prototypes (3 and 4) and the Medium. In Soumousso, both the original and Medium LFETs collected significantly greater numbers of mosquitoes compared to prototypes 3 and 4. Conclusion This study has shown that the new LFET prototypes are effective in trapping mosquitoes in high mosquito density settings. A large-scale study with one of the prototypes will be needed to assess community acceptance of the traps and their ability to control malaria vectors.

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Malaria vector species composition and entomological indices following indoor residual spraying in regions bordering Lake Victoria, Tanzania

Malaria Journal ◽

10.1186/s12936-020-03452-w ◽

2020 ◽

Vol 19 (1) ◽

Author(s):

Charles Kakilla ◽

Alphaxard Manjurano ◽

Karen Nelwin ◽

Jackline Martin ◽

Fabian Mashauri ◽

...

Keyword(s):

Species Composition ◽

Vector Control ◽

Malaria Vector ◽

Lake Victoria ◽

Indoor Residual Spraying ◽

Transmission Risk ◽

Malaria Vectors ◽

Vector Species ◽

Sporozoite Rate ◽

Pirimiphos Methyl

Abstract Background Vector control through long-lasting insecticidal nets (LLINs) and focal indoor residual spraying (IRS) is a major component of the Tanzania national malaria control strategy. In mainland Tanzania, IRS has been conducted annually around Lake Victoria basin since 2007. Due to pyrethroid resistance in malaria vectors, use of pyrethroids for IRS was phased out and from 2014 to 2017 pirimiphos-methyl (Actellic® 300CS) was sprayed in regions of Kagera, Geita, Mwanza, and Mara. Entomological surveillance was conducted in 10 sprayed and 4 unsprayed sites to determine the impact of IRS on entomological indices related to malaria transmission risk. Methods WHO cone bioassays were conducted monthly on interior house walls to determine residual efficacy of pirimiphos-methyl CS. Indoor CDC light traps with or without bottle rotator were hung next to protected sleepers indoors and also set outdoors (unbaited) as a proxy measure for indoor and outdoor biting rate and time of biting. Prokopack aspirators were used indoors to capture resting malaria vectors. A sub-sample of Anopheles was tested by PCR to determine species identity and ELISA for sporozoite rate. Results Annual IRS with Actellic® 300CS from 2015 to 2017 was effective on sprayed walls for a mean of 7 months in cone bioassay. PCR of 2016 and 2017 samples showed vector populations were predominantly Anopheles arabiensis (58.1%, n = 4,403 IRS sites, 58%, n = 2,441 unsprayed sites). There was a greater proportion of Anopheles funestus sensu stricto in unsprayed sites (20.4%, n = 858) than in sprayed sites (7.9%, n = 595) and fewer Anopheles parensis (2%, n = 85 unsprayed, 7.8%, n = 591 sprayed). Biting peaks of Anopheles gambiae sensu lato (s.l.) followed periods of rainfall occurring between October and April, but were generally lower in sprayed sites than unsprayed. In most sprayed sites, An. gambiae s.l. indoor densities increased between January and February, i.e., 10–12 months after IRS. The predominant species An. arabiensis had a sporozoite rate in 2017 of 2.0% (95% CI 1.4–2.9) in unsprayed sites compared to 0.8% (95% CI 0.5–1.3) in sprayed sites (p = 0.003). Sporozoite rates were also lower for An. funestus collected in sprayed sites. Conclusion This study contributes to the understanding of malaria vector species composition, behaviour and transmission risk following IRS around Lake Victoria and can be used to guide malaria vector control strategies in Tanzania.

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Linear and Spatial Organization of Polytene Chromosomes of the African Malaria Mosquito Anopheles funestus

Genetics ◽

10.1093/genetics/159.1.211 ◽

2001 ◽

Vol 159 (1) ◽

pp. 211-218

Author(s):

Igor V Sharakhov ◽

Maria V Sharakhova ◽

Charles M Mbogo ◽

Lizette L Koekemoer ◽

Guiyun Yan

Keyword(s):

Spatial Organization ◽

Polytene Chromosomes ◽

Genetic Research ◽

Anopheles Funestus ◽

Chromosome Morphology ◽

Pericentromeric Heterochromatin ◽

Malaria Vectors ◽

Malaria Mosquito ◽

Cytogenetic Map ◽

Important Species

Abstract Anopheles funestus Giles is one of the major malaria vectors in Africa, but little is known about its genetics. Lack of a cytogenetic map characterized by regions has hindered the progress of genetic research with this important species. This study developed a cytogenetic map of An. funestus using ovarian nurse cell polytene chromosomes. We demonstrate an important application with the cytogenetic map for characterizing various chromosomal inversions for specimens collected from coastal Kenya. The linear and spatial organization of An. funestus polytene chromosomes was compared with the best-studied malaria mosquito, An. gambiae Giles. Comparisons of chromosome morphology between the two species have revealed that the most extensive chromosomal rearrangement occurs in pericentromeric heterochromatin of autosomes. Differences in pericentromeric heterochromatin types correlate with nuclear organization differences between An. funestus and An. gambiae. Attachments of chromosomes to the nuclear envelope strongly depend on the presence of diffusive β-heterochromatin. Thus, An. funestus and An. gambiae exhibit species-specific characteristics in chromosome-linear and -spatial organizations.

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Heterogeneous exposure and hotspots for malaria vectors at three study sites in Uganda

Gates Open Research ◽

10.12688/gatesopenres.12838.2 ◽

2018 ◽

Vol 2 ◽

pp. 32 ◽

Cited By ~ 8

Author(s):

Su Yun Kang ◽

Katherine E. Battle ◽

Harry S. Gibson ◽

Laura V. Cooper ◽

Kilama Maxwell ◽

...

Keyword(s):

Malaria Transmission ◽

Malaria Vector ◽

Malaria Control ◽

Negative Binomial ◽

Indoor Residual Spraying ◽

Housing Quality ◽

Environmental Covariates ◽

Vector Density ◽

Vector Abundance ◽

Study Sites

Background: Heterogeneity in malaria transmission has household, temporal, and spatial components. These factors are relevant for improving the efficiency of malaria control by targeting heterogeneity. To quantify variation, we analyzed mosquito counts from entomological surveillance conducted at three study sites in Uganda that varied in malaria transmission intensity. Mosquito biting or exposure is a risk factor for malaria transmission. Methods: Using a Bayesian zero-inflated negative binomial model, validated via a comprehensive simulation study, we quantified household differences in malaria vector density and examined its spatial distribution. We introduced a novel approach for identifying changes in vector abundance hotspots over time by computing the Getis-Ord statistic on ratios of household biting propensities for different scenarios. We also explored the association of household biting propensities with housing and environmental covariates. Results: In each site, there was evidence for hot and cold spots of vector abundance, and spatial patterns associated with urbanicity, elevation, or other environmental covariates. We found some differences in the hotspots in rainy vs. dry seasons or before vs. after the application of control interventions. Housing quality explained a portion of the variation among households in mosquito counts. Conclusion: This work provided an improved understanding of heterogeneity in malaria vector density at the three study sites in Uganda and offered a valuable opportunity for assessing whether interventions could be spatially targeted to be aimed at abundance hotspots which may increase malaria risk. Indoor residual spraying was shown to be a successful measure of vector control interventions in Tororo, Uganda. Cement walls, brick floors, closed eaves, screened airbricks, and tiled roofs were features of a house that had shown reduction of household biting propensity. Improvements in house quality should be recommended as a supplementary measure for malaria control reducing risk of infection.

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