Efficacy of Vectobac DT and Culinexcombi Against Mosquito Larvae in Unused Swimming Pools in Malindi, Kenya

Kahindi, Samuel C.; Midega, Janet; Mwangangi, Joseph; Kibe, Lydiah W.; Nzovu, Joseph G.; Luethy, Peter; Githure, John I.; Mbogo, Charles M.

doi:10.2987/5734.1

Cited by 18 publications

(8 citation statements)

References 7 publications

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“…Studies within the East African region has shown similar results which indicates that there is significant reduction of Anopheles larvae after the Bti application (Barbazan et al 1998;Fillinger and Lindsay 2006;Kahindi et al 2008). For the culicines, the habitat type was important factor in determining the efficacy of the Bti/Bs biolarvicide.…”

Section: Habitat Type Early Instars Late Instars Early Instars Late Imentioning

confidence: 86%

“…The objective of this study was to evaluate large-scale application of a combined formulation of Bti/Bs biolarvicide (here referred to as Bti/Bs) in different aquatic habitats in urban and periurban Malindi, Kenya. This was a follow-up to our initial study which evaluated the efficacy of Vectobac DT and Culinex®Combi against mosquito larvae in unused swimming pools in Malindi, Kenya (Kahindi et al 2008).…”

Section: Introductionmentioning

confidence: 99%

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Wide-scale application of Bti/Bs biolarvicide in different aquatic habitat types in urban and peri-urban Malindi, Kenya

et al. 2010

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Larval control is a major component in mosquito control programs. This study evaluated the wide-scale application of Bti/Bs biolarvicide (Bacillus thuringiensis var. israelensis [Bti] and Bacillus sphaericus [Bs]) in different aquatic habitats in urban and peri-urban Malindi, Kenya. This study was done from June 2006 to December 2007. The urban and peri-urban area of Malindi town was mapped and categorized in grid cells of 1 km(2). A total of 16 1-km(2) cells were selected based on presence Community Based Organization dealing with malaria control within the cells. Each of the 16 1-km(2) cells was thoroughly searched for the presence of potential larval habitats. All habitats, whether positive or negative for larvae, were treated and rechecked 24 h (1 day), 6 days, and 10 days later for the efficacy of Bti/Bs. Weekly larval sampling was done to determine the mosquito larval dynamics in the aquatic habitats during the study period. Morphological identification of the mosquito larvae showed that Anopheles gambiae s.l. Giles was the most predominant species of the Anopheles and while in the culicines, Cx. quinquefasciatus Say was the predominant species. Anopheles larvae were all eliminated in habitats within a day post-application. For culicine larvae, 38.1% (n=8) of the habitat types responded within day 1 post-treatment and all the larvae were killed, they turned negative during the days of follow-up. Another 38.1% (n=8) of the habitat types had culicine larvae but turned negative by day 6, while three habitats (14.3%) had larvae by 6th day but turned negative by 10th day. However during this Bti/Bs application studies, two habitat types, house drainage and cesspits (9.5%), remained positive during the follow-up although the mosquito larvae were significantly reduced. Both early and late instars of Anopheles larvae immediately responded to Bti/Bs application and reached 100% mortality. The early and late instars of culicine responded to the Bti/Bs application but not as fast as the Anopheles larval instars. The early instars Culex, responded with 90.8% mortality at day 1 post-treatment, and the mortality was 99.9% at day 10. Similarly, the late instars Culex followed the same trend and exhibited same mortalities. The weekly sampling in the aquatic habitats showed that there was a 36.3% mosquito larval reduction in the aquatic habitats over the 18-months study period. In conclusion, Bti/Bs biolarvicide are useful in reducing the mosquito larval densities in a wide range of habitats which have a direct impact of adult mosquito populations.

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Section: Habitat Type Early Instars Late Instars Early Instars Late Imentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Wide-scale application of Bti/Bs biolarvicide in different aquatic habitat types in urban and peri-urban Malindi, Kenya

et al. 2010

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“…The appropriate management of larval habitats particularly during the dry season may help suppress vector densities and consequently, malaria transmission [29-31]. Recent studies in sub-Saharan Africa (SSA) have shown that larval control using microbial larvicide is effective in reducing adult densities in several countries including Kenya [32-34], Eritrea[35], Tanzania [36], Gambia [37] and can work in synergy with insecticide-treated bed nets to significantly lower malaria transmission [38]. However, our understanding of anopheline larval ecology in rice agro-ecosystems is still insufficient and this affects the design and implementation of larval control.…”

Section: Introductionmentioning

confidence: 99%

Anopheles larval abundance and diversity in three rice agro-village complexes Mwea irrigation scheme, central Kenya

Mwangangi

Shililu

Muturi

et al. 2010

Malar J

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BackgroundThe diversity and abundance of Anopheles larvae has significant influence on the resulting adult mosquito population and hence the dynamics of malaria transmission. Studies were conducted to examine larval habitat dynamics and ecological factors affecting survivorship of aquatic stages of malaria vectors in three agro-ecological settings in Mwea, Kenya.MethodsThree villages were selected based on rice husbandry and water management practices. Aquatic habitats in the 3 villages representing planned rice cultivation (Mbui Njeru), unplanned rice cultivation (Kiamachiri) and non-irrigated (Murinduko) agro-ecosystems were sampled every 2 weeks to generate stage-specific estimates of mosquito larval densities, relative abundance and diversity. Records of distance to the nearest homestead, vegetation coverage, surface debris, turbidity, habitat stability, habitat type, rice growth stage, number of rice tillers and percent Azolla cover were taken for each habitat.ResultsCaptures of early, late instars and pupae accounted for 78.2%, 10.9% and 10.8% of the total Anopheles immatures sampled (n = 29,252), respectively. There were significant differences in larval abundance between 3 agro-ecosystems. The village with 'planned' rice cultivation had relatively lower Anopheles larval densities compared to the villages where 'unplanned' or non-irrigated. Similarly, species composition and richness was higher in the two villages with either 'unplanned' or limited rice cultivation, an indication of the importance of land use patterns on diversity of larval habitat types. Rice fields and associated canals were the most productive habitat types while water pools and puddles were important for short periods during the rainy season. Multiple logistic regression analysis showed that presence of other invertebrates, percentage Azolla cover, distance to nearest homestead, depth and water turbidity were the best predictors for Anopheles mosquito larval abundance.ConclusionThese results suggest that agricultural practices have significant influence on mosquito species diversity and abundance and that certain habitat characteristics favor production of malaria vectors. These factors should be considered when implementing larval control strategies which should be targeted based on habitat productivity and water management.

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“…quinquefasciatus [90,91], and during a study conducted in China where the toxicity of Bti was demonstrated for larvae of Aedes, Culex and Anopheles, especially for the last two [92]. In Kenya and in India, [93,94] also observed susceptibility to Bti on the larvae of the last stages of An. gambiae complex and Cx.…”

Section: Effect Of Bacillus Thuringiensis Var Israelensis (Bti)mentioning

confidence: 99%

Susceptibility of mosquito vectors of the city of Praia, Cabo Verde, to Temephos and Bacillus thuringiensis var israelensis

Pires

Alves²,

Dia

et al. 2020

PLoS ONE

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Many vector-borne diseases circulate in the Republic of Cabo Verde. These include malaria during the colonization of the archipelago by the Portuguese explorers and several arboviruses such as yellow fever (now eradicated), dengue and zika. To control these vector-borne diseases, an integrated vector control program was implemented. The main targeted mosquito vectors are Aedes aegypti and Anopheles arabiensis, and in a lesser extent the potential arbovirus vector Culex pipiens s.l. The main control strategy is focused on mosquito aquatic stages using diesel oil and Temephos. This latter has been applied in Cabo Verde since 1979. Its continuous use was followed by the emergence of resistance in mosquito populations. We investigated the current susceptibility to Temephos of the three potential mosquito vectors of Cabo Verde through bioassays tests. Our results showed various degrees of susceptibility with 24h post-exposure mortality rates ranging from 43.1% to 90.9% using WHO diagnostic doses. A full susceptibility was however observed with Bacillus thurigiensis var israelensis with mortality rates from 99.6% to 100%.

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Efficacy of Vectobac DT and Culinexcombi Against Mosquito Larvae in Unused Swimming Pools in Malindi, Kenya

Cited by 18 publications

References 7 publications

Wide-scale application of Bti/Bs biolarvicide in different aquatic habitat types in urban and peri-urban Malindi, Kenya

Wide-scale application of Bti/Bs biolarvicide in different aquatic habitat types in urban and peri-urban Malindi, Kenya

Anopheles larval abundance and diversity in three rice agro-village complexes Mwea irrigation scheme, central Kenya

Susceptibility of mosquito vectors of the city of Praia, Cabo Verde, to Temephos and Bacillus thuringiensis var israelensis

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