Comparison of bednets treated with alphacypermethrin, permethrin or lambdacyhalothrin against <i>Anopheles gambiae</i> in the Gambia

Jawara,; Mcbeath,; Pinder,; Sanyang,; Greenwood,

doi:10.1046/j.1365-2915.1998.00083.x

Cited by 21 publications

(26 citation statements)

References 21 publications

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“…In The Gambia, Miller et al [23] observed a 85% reduction in insecticide content after three washes which is very close to the findings in Uganda. In contrast, Jawara and co-workers [24] found An. gambiae s.l .…”

Section: Discussionmentioning

confidence: 85%

Evidence for a useful life of more than three years for a polyester-based long-lasting insecticidal mosquito net in Western Uganda

Kilian

Byamukama

Pigeon

et al. 2011

Malar J

111

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BackgroundLong-lasting insecticidal nets (LLIN) are now standard for the prevention of malaria. However, only products with recommendation for public use from the World Health Organization should be used and this evaluation includes the assessment of net effectiveness after three years of field use. Results for one of the polyester-based products, Interceptor® is presented.MethodsIn five villages, 190 LLIN and 90 nets conventionally treated with the insecticide alpha-cypermethrin at 25 mg/m2 were distributed randomly and used by the families. Following a baseline household survey a net survey was carried out every six months to capture use, washing habits and physical condition of the nets. Randomly selected nets were collected after 6, 12, 24, 36 and 42 months and tested for remaining insecticide content and ability to knock-down and kill malaria transmitting mosquitoes.ResultsDuring the three and a half years of observation only 16 nets were lost to follow-up resulting in an estimated attrition rate of 12% after three and 20/% after 3.5 years. Nets were used regularly and washed on average 1.5 times per year. After three and a half years 29% of the nets were still in good condition while 13% were seriously torn with no difference between the LLIN and control nets. The conventionally treated nets quickly lost insecticide and after 24 months only 7% of the original dose remained (1.6 mg/m2). Baseline median concentration of alpha-cypermethrin for LLIN was 194.5 mg/m2 or 97% of the target dose with between and within net variation of 11% and 4% respectively (relative standard deviation). On the LLIN 73.8 mg/m2 alpha-cypermethrin remained after three years of use and 56.2 mg/m2 after three and a half and 94% and 81% of the LLIN still had > 15 mg/m2 left respectively. Optimal effectiveness in bio-assays (≥95% 60 minute knock-down or ≥ 80% 24 hour mortality) was found in 83% of the sampled LLIN after three and 71% after three and a half years.ConclusionsUnder conditions in Western Uganda the tested long-lasting insecticidal net Interceptor® fulfilled the criteria for phase III of WHO evaluations and, based on preliminary criteria of the useful life, this product is estimated to last on average between three and four years.

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Section: Discussionmentioning

confidence: 85%

Evidence for a useful life of more than three years for a polyester-based long-lasting insecticidal mosquito net in Western Uganda

Kilian

Byamukama

Pigeon

et al. 2011

Malar J

111

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“…In failing to deter or repel many mosquitoes, nets treated with a-cypermethrin and deltamethrin are in contact with many hostseeking mosquitoes for relatively long periods of time, during which the insects are likely to pick up a lethal dose of the insecticide from the treated surface. When, in The Gambia, Jawara et al (1998) compared net performances in the field, they found nets treated with a-cypermethrin (at 40 mg/m 2 ) to kill more mosquitoes than nets treated with permethrin (at 500 mg/m 2 ) or l-cyhalothrin (at 10 mg/m 2 ).…”

Section: Discussionmentioning

confidence: 99%

“…In these trials, more An. gambiae s.s. were killed by a-cypermethrin than by permethrin or l-cyhalothrin (Jawara et al, 1998). There has been no similar evaluation of the performance of nets treated with commonly used insecticides against An.…”

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confidence: 96%

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Comparative efficacies of permethrin-, deltamethrin- andα-cypermethrin-treated nets, againstAnopheles arabiensisandCulex quinquefasciatusin northern Tanzania

Mosha

Lyimo

Oxborough

et al. 2008

Annals of Tropical Medicine & Parasitology

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Mosquito nets treated with permethrin, deltamethrin or alpha-cypermethrin at 25 mg/m(2) were evaluated in experimental huts in an area of rice irrigation near Moshi, in northern Tanzania. The nets were deliberately holed to resemble worn nets. The nets treated with permethrin offered the highest personal protection against Anopheles arabiensis (61.6% reduction in fed mosquitoes) and Culex quinquefasciatus (25.0%). Deltamethrin and alpha-cypermethrin provided lower personal protection against An. arabiensis (46.4% and 45.6%, respectively) and no such protection against Cx. quinquefasciatus. Permethrin performed poorly in terms of mosquito mortality, however, killing only 15.2% of the An. arabiensis and 9.2% of the Cx. quinquefasciatus exposed to the nets treated with this pyrethroid (after correcting for control mortality). The alpha-cypermethrin and deltamethrin performed marginally better, with respective mortalities of 32.8% and 33.0% for An. arabiensis and 19.4% and 18.9% for Cx quinquefasciatus. The poor killing effect of permethrin was confirmed in a second trial where a commercial, long-lasting insecticidal net based on this pyrethroid (Olyset) produced low mortalities in both An. arabiensis (11.8%) and Cx. quinquefasciatus (3.6%). Anopheles arabiensis survivors collected from the verandahs of the experimental huts and tested on 0.75%-permethrin and 0.05%-deltamethrin papers, in World Health Organization susceptibility kits, showed mortalities of 96% and 100%, respectively. The continued use of permethrin-treated nets is recommended for personal protection against An. arabiensis. In control programmes that aim to interrupt transmission of pathogens by mosquitoes and/or manage pyrethroid resistance in such vectors, a combination of a pyrethroid and another insecticide with greater killing effect should be considered.

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“…However, due to limitations in the methodologies used, the results of such studies have only given rough estimates of insecticide concentrations. Bioassays of susceptible mosquitoes on treated bednets can be used to obtain an indication of biological activity of ITNs, using a correlation between the mortality rates in test mosquitoes and exposure time (Beach et al, 1993;Jawara et al, 1998;Jinjiang et al, 1988;Lindsay et al, 1991aLindsay et al, , 1993Maxwell et al, 1999). However, this method is not particularly sensitive and requires access to susceptible live mosquitoes, a requirement beyond most ITN programmes.…”

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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Comparison of bednets treated with alphacypermethrin, permethrin or lambdacyhalothrin against Anopheles gambiae in the Gambia

Cited by 21 publications

References 21 publications

Evidence for a useful life of more than three years for a polyester-based long-lasting insecticidal mosquito net in Western Uganda

Evidence for a useful life of more than three years for a polyester-based long-lasting insecticidal mosquito net in Western Uganda

Comparative efficacies of permethrin-, deltamethrin- andα-cypermethrin-treated nets, againstAnopheles arabiensisandCulex quinquefasciatusin northern Tanzania

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

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