Dynamics of the Pyrethroid Knockdown Resistance Allele in Western Kenyan Populations of Anopheles Gambiae in Response to Insecticide-Treated Bed Net Trials

Stump, Aram D.; Atieli, Francis; Vulule, John; Besansky, Nora J.

doi:10.4269/ajtmh.2004.70.591

Cited by 156 publications

(179 citation statements)

References 40 publications

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“…Since no any other sibling species apart from Anopheles arabiensis was identified by molecular means, it is unlikely that any of the failed amplifications would identify to any other sibling species. In previous studies from the same region A. arabiensis mosquitoes were found to be the only sibling species of A. gambiae complex mosquitoes [33,34,31]. In a study carried out at Mwea rice irrigation scheme, A. arabiensis mosquitoes were found to be the only member of A. gambiae complex mosquitoes [35].…”

Section: Discussionmentioning

confidence: 99%

Knock down efficacy of commercially available insecticides against Anopheles gambiae

2017

J App Biol Biotech

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Knockdown efficacy of commercial aerosol insecticides against laboratory reared Anopheles gambiae Kisumu strain mosquitoes and suppression of indoor resting density of A. gambiae complex mosquitoes in the field were investigated in the study. Laboratory reared 2-5 days old female A. gambiae mosquitoes were released into Peet-Grady chambers, sprayed with 0.3±0.1g of insecticides. Knock down rates were observed for one hour and mortality rates after 24hrs of spraying. Field efficacy studies were carried out by spraying houses with near uniform indoor resting densities of A. gambiae complex mosquitoes with aerosol insecticides and mosquitoes collected. Morphological and molecular characterization of mosquitoes was done. Probit analysis on knock down rates was carried out. Mortality rates and Mean indoor resting densities were compared using ANOVA in SPSS version 16. The KT50 and KT95 of Kenyan Baygon ® and Kenyan raid ® differed significantly with the other insecticides. Nigerian Baygon ® achieved the lowest mortality rate of 87% and differed significantly (P<0.05) with other insecticides. No significant differences in suppression of indoor resting densities of A. gambiae complex mosquitoes was observed (p>0.05). Collected A. gambiae complex mosquitoes corresponded to A. arabiensis. The low knock down values by Kenyan Baygon ® , Kenyan raid ® and the low mortality rate by Nigerian Baygon ® can be attributed to reduced efficacy rather than development of resistance. Whether the low deterrence of Anopheles gambiae complex mosquitoes into houses is due to development of pyrethroid insecticide resistance can be authenticated in another study.

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Section: Discussionmentioning

confidence: 99%

Knock down efficacy of commercially available insecticides against Anopheles gambiae

2017

J App Biol Biotech

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“…Our survey found that occasional agricultural insecticide use in Kenya was primarily in the rice, coffee/tea plantation and sugar cane growing areas while other areas reported little use of insecticides . Stump et al (2004) reported that the frequency of the kdr allele in An. gambiae increased from 3-4% to 4-8% after 7-8 years of using pyrethroid-treated bednets in an ITN trial area in Asembo Bay, west Kenya.…”

Section: Discussionmentioning

confidence: 99%

“…Permethrin knock-down resistance has arisen independently at least twice in Africa. In west Africa, kdr was caused by a leucine-phenylalanine substitution at position 1014 of the sodium channel gene (L1014F) whereas a different mutation (leucine-serine substitution) at the same amino acid position (L1014S) was associated with kdr resistance in Kenya in both A. gambiae and A. arabiensis (Martinez-Torres et al 1998;Ranson et al 2000;Stump et al 2004). However, the L1014F mutation has been detected in An.…”

Section: Introductionmentioning

confidence: 99%

Monooxygenase Levels and Knockdown Resistance (kdr) Allele Frequencies in Anopheles gambiae and Anopheles arabiensis in Kenya

Chen

Githeko

Githure

et al. 2008

Journal of Medical Entomology

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Pyrethroid-treated bed nets and indoor spray are important components of malaria control strategies in Kenya. Information on resistance to pyrethroid insecticides in Anopheles gambiae and An. arabiensis populations is essential to the selection of appropriate insecticides and the management of insecticide resistance. Monooxygenase activity and knockdown resistance (kdr) allele frequency are biochemical and molecular indicators of mosquito resistance to pyrethroids. This study determined baseline information on monooxygenase activity and kdr allele frequency in anopheline mosquitoes in the western region, the Great Rift Valley-central province region, and the coastal region of Kenya. A total of 1990 field-collected individuals, representing 12 An. gambiae and 22 An. arabiensis populations was analyzed. We found significant among-population variation in monooxygenase activity in An. gambiae and An. arabiensis and substantial variability among individuals within populations. Nine out of 12 An. gambiae populations exhibited significantly higher average monooxygenase activity than the susceptible Kisumu reference strain. The kdr alleles (L1014S) were detected in three An. gambiae populations, and one An. arabiensis population in western Kenya, but not in the Rift Valley-central region and the coastal Kenya region. All genotypes with the kdr alleles were heterozygous, and the conservative estimation of kdr allele frequency was below 1% in these four populations. Information on monooxygenase activity and kdr allele frequency reported in this study provided baseline data for monitoring insecticide resistance changes in Kenya during the era when large-scale insecticide-treated bednet and indoor residual spray campaigns were being implemented.

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“…Both mutations have also been reported to co-exist in Gabon and Cameroon [106] and in Uganda [107]. The western kdr was also detected in Kenya [108], Tanzania [109], and also in Zambia [110,111]. In pyrethroid-resistant An.…”

Section: Distribution Of Insecticide Resistancementioning

confidence: 99%

Optimizing Strategic Insecticide Resistance Management Planning in Malaria Vectors

Chanda¹

2016

Insecticides Resistance

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In the past decade, there has been rapid scale-up of insecticide-based malaria vector control in the context of integrated vector management (IVM). But, the continued efficacy of vector control interventions is threatened by the selection of insecticide resistance. Evidence of insecticide resistance operationally undermining malaria vector control programmes is invariably mounting and is resulting in policy changes. Monitoring and management of resistant disease vectors is essential to limit the selection and spread of insecticide resistance and to maintain the effectiveness of vector control. Thus, countries are encouraged to implement pre-emptive insecticide resistance management (IRM) strategies against malaria vectors according to the Global Plan for IRM. However, substantial challenges for implementation exist at country level. The IVM strategy provides a potential platform that could be exploited for enhanced national strategic IRM planning and operationalisation. Nevertheless, significant coordinated response among stakeholders and political commitment is needed for timely and effective policy implementation within the context of a national health system.

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Dynamics of the Pyrethroid Knockdown Resistance Allele in Western Kenyan Populations of Anopheles Gambiae in Response to Insecticide-Treated Bed Net Trials

Cited by 156 publications

References 40 publications

Knock down efficacy of commercially available insecticides against Anopheles gambiae

Knock down efficacy of commercially available insecticides against Anopheles gambiae

Monooxygenase Levels and Knockdown Resistance (kdr) Allele Frequencies in Anopheles gambiae and Anopheles arabiensis in Kenya

Optimizing Strategic Insecticide Resistance Management Planning in Malaria Vectors

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