Net Benefits: A Multicountry Analysis of Observational Data Examining Associations between Insecticide-Treated Mosquito Nets and Health Outcomes

Lim, Stephen S; Fullman, Nancy; Stokes, Andrew; Ravishankar, Nirmala; Masiye, Felix; Murray, Christopher J L; Gakidou, Emmanuela

doi:10.1371/journal.pmed.1001091

Cited by 157 publications

(177 citation statements)

References 25 publications

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“…1,2 The insecticide in ITNs kills mosquitoes seeking a blood meal, which reduces indoor vector densities. 3 Furthermore, if the person under the net is already infected with the malaria parasite, the ITN reduces transmission by preventing gametocyte uptake by mosquitoes.…”

Section: Introductionmentioning

confidence: 99%

Community Coverage with Insecticide-Treated Mosquito Nets and Observed Associations with All-Cause Child Mortality and Malaria Parasite Infections

Larsen

Hutchinson

Bennett

et al. 2014

The American Society of Tropical Medicine and Hygiene

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Abstract. Randomized trials and mathematical modeling suggest that insecticide-treated mosquito nets (ITNs) provide community-level protection to both those using ITNs and those without individual access. Using nationally representative household survey datasets from 17 African countries, we examined whether community ITN coverage is associated with malaria infections in children 5 years old and all-cause child mortality (ACCM) among children 5 years old in households with one or more ITNs versus without any type of mosquito net (treated or untreated). Increasing ITN coverage ( 50%) was protective against malaria infections and ACCM for children in households with an ITN, although this protection was not conferred to children in households without ITNs in these data. Children in households with ITNs were protected against malaria infections and ACCM with ITN coverage 30%, but this protection was not significant with ITN coverage 30%. Results suggest that ITNs are more effective with higher ITN coverage. BACKGROUND

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Section: Introductionmentioning

confidence: 99%

Community Coverage with Insecticide-Treated Mosquito Nets and Observed Associations with All-Cause Child Mortality and Malaria Parasite Infections

Larsen

Hutchinson

Bennett

et al. 2014

The American Society of Tropical Medicine and Hygiene

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“…kdr | selective sweep | inactivation particle T he impetus to eradicate malaria has yielded a significant reduction of malaria mortality and morbidity via antiparasite artemisinin combination therapies (1) and scaling up of coverage with insecticide-based interventions (2). Vector control interventions are based primarily around either provision of longlasting insecticide-treated nets (LLINs) or indoor residual spraying of insecticide onto surfaces where mosquitoes rest after blood feeding.…”

mentioning

confidence: 99%

Footprints of positive selection associated with a mutation ( N1575Y ) in the voltage-gated sodium channel of Anopheles gambiae

Jones

Liyanapathirana²,

Agossa³

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

208

245

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Insecticide resistance is an ideal model to study the emergence and spread of adaptative variants. In the African malaria mosquito, Anopheles gambiae, this is complemented by a strong public health rationale. In this insect, resistance to pyrethroid and DDT insecticides is strongly associated with the mutations L1014F and L1014S within the para voltage-gated sodium channel (VGSC). Across much of West Africa, 1014F frequency approaches fixation. Here, we document the emergence of a mutation, N1575Y, within the linker between domains III-IV of the VGSC. In data extending over 40 kbp of the VGSC 1575Y occurs on only a single long-range haplotype, also bearing 1014F. The 1014F-1575Y haplotype was found in both M and S molecular forms of An. gambiae in West/ Central African sample sites separated by up to 2,000 km. In Burkina Faso M form, 1575Y allele frequency rose significantly from 0.053 to 0.172 between 2008 and 2010. Extended haplotype homozygosity analysis of the wild-type 1575N allele showed rapid decay of linkage disequilibrium (LD), in sharp contrast to the extended LD exhibited by 1575Y. A haplotype with long-range LD and high/increasing frequency is a classical sign of strong positive selection acting on a recent mutant. 1575Y occurs ubiquitously on a 1014F haplotypic background, suggesting that the N1575Y mutation compensates for deleterious fitness effects of 1014F and/or confers additional resistance to insecticides. Haplotypic tests of association suggest the latter: The 1014F-1575Y haplotype confers a significant additive benefit above 1014F-1575N for survival to DDT (M form P = 0.03) and permethrin (S form P = 0.003).kdr | selective sweep | inactivation particle

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“…Despite remarkable success in reducing malaria burdens between 2000 and 2010 through the use of treated bednets (12)(13)(14), the epidemiology of malaria in these settings has also become more complex (50,(58)(59)(60), which is likely reflective of transient dynamics of immunity (61). Notably, in many of the Sub-Saharan African countries, trajectories of adult and child mortality have been following seemingly unrelated trends over the past decade, with increasing ratios of adult to child morbidity, as illustrated in SI Appendix, section VI.…”

Section: Discussionmentioning

confidence: 99%

“…In the past decade, insecticide-treated bednets (ITN) and long-lasting insecticide-treated nets have proven to be highly effective in reducing rates of malaria mortality in young children (12)(13)(14); differences between these are discussed in Methods. [Note that we use ITN to represent both insecticidetreated bednets and long-lasting insecticide-treated nets (LLINs)].…”

mentioning

confidence: 99%

Synergistic and antagonistic interactions between bednets and vaccines in the control of malaria

Artzy‐Randrup

Dobson

Pascual

2015

Proc. Natl. Acad. Sci. U.S.A.

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It is extremely likely that the malaria vaccines currently in development will be used in conjunction with treated bednets and other forms of malaria control. The interaction of different intervention methods is at present poorly understood in a disease such as malaria where immunity is more complex than for other pathogens that have been successfully controlled by vaccination. Here we develop a general mathematical model of malaria transmission to examine the interaction between vaccination and bednets. Counterintuitively, we find that the frailty of malaria immunity will potentially cause both synergistic and antagonistic interactions between vaccination and the use of bednets. We explore the conditions that create these tensions, and outline strategies that minimize their detrimental impact. Our analysis specifically considers the three leading vaccine classes currently in development: preerythrocytic (PEV), blood stage (BSV), and transmission blocking (TBV). We find that the combination of BSV with treated bednets can lead to increased morbidity with no added value in terms of elimination; the interaction is clearly antagonistic. In contrast, there is strong synergy between PEV and treated bednets that may facilitate elimination, although transient stages are likely to increase morbidity. The combination of TBV with treated bednets is synergistic, lowering both morbidity and elimination thresholds. Our results suggest that vaccines will not provide a straightforward solution to malaria control, and that future programs need to consider the synergistic and antagonistic interactions between vaccines and treated bednets.

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Net Benefits: A Multicountry Analysis of Observational Data Examining Associations between Insecticide-Treated Mosquito Nets and Health Outcomes

Cited by 157 publications

References 25 publications

Community Coverage with Insecticide-Treated Mosquito Nets and Observed Associations with All-Cause Child Mortality and Malaria Parasite Infections

Community Coverage with Insecticide-Treated Mosquito Nets and Observed Associations with All-Cause Child Mortality and Malaria Parasite Infections

Footprints of positive selection associated with a mutation ( N1575Y ) in the voltage-gated sodium channel of Anopheles gambiae

Synergistic and antagonistic interactions between bednets and vaccines in the control of malaria

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