Insecticide-treated bednets and curtains for preventing malaria

Lengeler, Christian

doi:10.1002/14651858.cd000363

Cited by 256 publications

(270 citation statements)

References 88 publications

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“…Yet the efficacy of ITNs in community randomized trials with UTNs as control was lower than that where control groups had no nets, suggesting that UTNs have a positive, although small, efficacy (LENGELER, 1998).…”

Section: Discussionmentioning

confidence: 94%

“…It has consequently been proposed that the apparent beneficial effects of UTNs in some studies might merely reflect diversion of frustrated host-seeking mosquitoes on to unprotected individuals sleeping nearby (SNOW er at., 1988a(SNOW er at., , 1988b1998). Differences in infection rates between UTN users and unprotected individuals would then reflect redistribution of bites rather than net decreases in inoculations, and thus widespread use of UTNs would have little overa public health impact, possibly even disadvantaging those who could not obtain them.…”

mentioning

confidence: 99%

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Area effects of bednet use in a malaria-endemic area in Papua New Guinea

Hii

Smith

Vounatsou

et al. 2001

Transactions of the Royal Society of Tropical Medicine and Hygi

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Relationships between area coverage with insecticide-free bednets and prevalence of Plusvv~udiumfalcipanrm were investigated in 7 community-based surveys over a 33-month period in 1990-93 in 6 villages in the Wosera area of Papua New Guinea. Spatial patterns in circumsporozoite rates for I? jalciparum, I? oivax isomorphs K210 and K247, and i? mah-iae, and the proportions of mosquito blood meals positive for specific human, goat, cat, dog and pig antigens were determined using ELISAs. I? fakiparulm prevalence in humans was better explained by bednet coverage in the immediate vicinity than by personal protection alone. Circumsporozoite rates for both P jalci@rum and I? &ax were also inversely related to coverage with bednets. There was some increase in zoophagy in areas with high coverage, but relatively little effect on the human blood index or on overall mosquito densities. In this setting, protracted use ofuntreated bednets apparently reduces sporozoite rates, and the associated effects on prevalence are greater than can be accounted for by personal protection. Even at high bednet coverage most anophe1ines feed on human hosts, so the decreased sporozoite rates are likely to be largely due to reduction of mosquito survival. This finding highlights the importance of local vector ecology for outcomes of bednet programmes and suggests that area effects ofuntreated bednets should be reassessed in other settings,

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Section: Discussionmentioning

confidence: 94%

mentioning

confidence: 99%

Area effects of bednet use in a malaria-endemic area in Papua New Guinea

Hii

Smith

Vounatsou

et al. 2001

Transactions of the Royal Society of Tropical Medicine and Hygi

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“…and a meta-analysis of the trials found an overall estimate of protective efficacy of 19% (Lengeler 1998). In addition, economic evaluations of these trials have shown the use of ITNs to be relatively cost-effective, with a cost per discounted year of life saved ranging from US$9 to $77, and a cost per death averted ranging from $219 to $2958 (in 1995 prices) (Picard et al 1993;Binka et al 1997;Aikins et al 1998;Some 1998).…”

Section: Tmih382mentioning

confidence: 99%

Rebound mortality and the cost‐effectiveness of malaria control: potential impact of increased mortality in late childhood following the introduction of insecticide treated nets

Coleman¹,

Goodman²,

Mills³

1999

Tropical Med Int Health

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SummaryThe efficacy and relative cost-effectiveness of insecticide-treated nets (ITNs) for the control of malaria in children under 5 years of age have recently been demonstrated by several large-scale trials. However, it has been suggested that long-term use of ITNs in areas of high transmission could lead to mortality rebound in later childhood, which would reduce the cost-effectiveness of the intervention, and at the extreme could lead to negative overall effects. A model is presented in which the cost and disability adjusted life years (DALYs) per child aged 1-119 months were estimated for a sub-Saharan African population with and without an ITN intervention. The rebound rate, defined as the percentage increase in age-specific all-cause mortality and malaria specific-morbidity, was varied to estimate the threshold at which the intervention was no longer costeffective. Rebound was considered over two possible age ranges: 5-9 years and 3-6 years. With mortality and morbidity reductions due to ITNs in children aged 1-59 months and rebound in the 5-9 years age class, one could be reasonably certain that the cost per DALY averted is below $150 up to a rebound rate of 39%. Up to an 84% rebound rate it is highly likely that the intervention will be DALY-averting, that is the DALYs averted by the intervetion outweigh DALYs incurred through rebound effects. These thresholds are sensitive to the age range over which reductions and rebound in morbidity and mortality occur. With reductions confined to children aged 1-35 months and rebound in the 3-6 years age class, the cost per DALY is highly likely to fall below $150 only up to a 2.5% rebound rate, and with a rate in excess of 11% one can no longer be reasonably certain that the intervention is DALY-averting. These rates apply to the whole population. If there is no rebound amongst children who did not comply with the intervention, the actual increases in morbidity and mortality required to reach these thresholds amongst compliers would be much higher. The age range over which rebound occurs is a critical determinant of the thresholds at which one can no longer be reasonably certain that ITNs remain cost-effective in the long term. Based on empirical estimates of age-specific malaria mortality in sub-Saharan Africa, it appears unlikely that this threshold rate would be reached if rebound occurs over the 5-9 years age range. By contrast, if rebound occurs over the ages of 3-6 years, the increase in mortality rates required to reach this threshold falls within the observed range of malaria-specific mortality rates for this age group. It is essential that long-term surveillance is included as part of ITN interventions, with particular attention to the age range over which rebound may occur.

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“…The international public health community, and the African Heads of State who met in Abuja, Nigeria, in 2000, have committed themselves to protecting 60% of all pregnant women and small children with ITNs by 2005. In endemic areas, ITNs reduce the number of clinical malaria episodes by roughly 50% and improve infant survival by nearly a fifth (Lengeler, 2000).…”

Section: Introductionmentioning

confidence: 99%

“…This is a problem for two reasons. Firstly, nets that are not treated with insecticide provide only about half the epidemiological impact that treated nets have (Lengeler, 2000). Hence, the failure to add the insecticide, by far the cheaper of the two ITN components (net and insecticide), means that a large impact is missed.…”

Section: Introductionmentioning

confidence: 99%

Field evaluation of a recombinant glutathione S-transferase-based pyrethroid quantification assay

Enayati¹,

Lengeler²,

Erlanger³

et al. 2005

Transactions of the Royal Society of Tropical Medicine and Hygi

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Summary A recombinant glutathione S-transferase (GST)-based pyrethroid quantification assay was field-tested in Ifakara, Tanzania. Initial laboratory tests suggested that all reagents used in the assay should be sufficiently stable for field use, provided that domestic refrigeration facilities were available. Insecticideimpregnated bednets were collected from a region where a social marketing programme was in progress. A total of 100 bednets were collected and the assay plus standard HPLC analysis was performed on the residues extracted from four replicate areas of each net. Insecticide residue estimations for assays performed on white and pale green bednet samples were accurate when compared with residue analysis by HPLC. However, for dark green or blue bednets, there was no correlation between the GST-based assay and HPLC pyrethroid quantification results. The assay failure with the dark coloured nets was caused by the extraction of the dyes along with the insecticide, which subsequently interfered with the GST assay. When the same samples were analysed by HPLC, the dyes were separated from the insecticide by reverse phase column chromatography and hence did not affect the results.

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Insecticide-treated bednets and curtains for preventing malaria

Abstract: This record should be cited as: Lengeler C. Insecticide-treated bednets and curtains for preventing malaria. The Cochrane Database of Systematic Reviews (Complete Reviews) , Issue . Art. No.: CD000363.

Cited by 256 publications

References 88 publications

Area effects of bednet use in a malaria-endemic area in Papua New Guinea

Area effects of bednet use in a malaria-endemic area in Papua New Guinea

Rebound mortality and the cost‐effectiveness of malaria control: potential impact of increased mortality in late childhood following the introduction of insecticide treated nets

Field evaluation of a recombinant glutathione S-transferase-based pyrethroid quantification assay

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