Field effectiveness of microbial larvicides on mosquito larvae in malaria areas of Botswana and Zimbabwe

dc.contributor.authorMpofu, Mulamuli
dc.contributor.authorBecker, Piet J.
dc.contributor.authorMudambo, Kaka
dc.contributor.authorDe Jager, Christiaan
dc.contributor.emailtiaan.dejager@up.ac.zaen_ZA
dc.date.accessioned2017-01-25T09:09:18Z
dc.date.available2017-01-25T09:09:18Z
dc.date.issued2016-12-06
dc.description.abstractBACKGROUND : The successful control of malaria vectors requires the control of both the larval and adult stages. The adult control methods through indoor residual spraying (IRS) and use of long-lasting insecticidal nets (LLINs) continue to be widely used with some high measure of success. Larval control methods are also being used by a number of National Malaria Control Programmes (NMCPs) with limited understanding of its contribution. Larval control might be needed in some areas to move from malaria control to elimination. This experimental study was conducted to assess the field effectiveness of winter larviciding on the larval stages of the mosquito in Botswana and Zimbabwe. METHODS : Two villages were selected in each of the two countries, one as an intervention and the other as the control. Water bodies in the intervention villages were treated using the commercial product VectoBac® WG (Valent BioSciences Corporation, IL, USA) containing the active ingredient Bacillus thuringiensis var. israelensis (Bti), a WHO recommended bio-larvicide, applied at a rate of 300 g per hectare. Random-effects Poisson regression was employed during data analysis to compare intervention with control sites with respect to larval counts. RESULTS : The average marginal effect of larviciding on the mosquito larvae taking interaction with time (period) into account, was −1.94 (95% CI −2.42 to −1.46) with incidence rate ratio of 0.14, thus an 86% larval reduction attributable to the intervention for both countries combined. There was a 92% and 65% effect for Botswana and Zimbabwe respectively. The effect on the early larval and late stages was 77% (P < 0.001) and 91% (P < 0.001), respectively. Overall, intervention larval sampling points had five more larvae than the control at baseline and 26 less after 16 weeks. The effect on the different species also showed similar trends. DISCUSSION/CONCLUSION : Larval control using Bti showed a high effect on the population of the mosquito larvae. The reduction of the early and late larval stages can lead to reduced adult mosquito emergence and low adult mosquito densities. Larviciding can be used to control mosquito vector population by suppressing the larval stages thereby reducing adult emergence and malaria risk.en_ZA
dc.description.departmentSchool of Health Systems and Public Health (SHSPH)en_ZA
dc.description.librarianam2017en_ZA
dc.description.sponsorshipThe University of Pretoria Institute for Sustainable Malaria Controlen_ZA
dc.description.urihttp://www.malariajournal.comen_ZA
dc.identifier.citationMpofu, M, Becker, P, Mudambo, K & De Jager, C 2016, 'Field effectiveness of microbial larvicides on mosquito larvae in malaria areas of Botswana and Zimbabwe', Malaria Journal, vol. 15, art. no. 586, pp. 1-8.en_ZA
dc.identifier.issn1475-2875
dc.identifier.other10.1186/s12936-016-1642-6
dc.identifier.urihttp://hdl.handle.net/2263/58634
dc.language.isoenen_ZA
dc.publisherBioMed Centralen_ZA
dc.rights© The Author(s) 2016. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License.en_ZA
dc.subjectLarvicidingen_ZA
dc.subjectMicrobial larvicidesen_ZA
dc.subjectBotswanaen_ZA
dc.subjectZimbabween_ZA
dc.subjectMalaria vector controlen_ZA
dc.subjectIndoor residual spraying (IRS)en_ZA
dc.subjectLong-lasting insecticidal nets (LLINs)en_ZA
dc.subjectNational malaria control programmes (NMCPs)en_ZA
dc.titleField effectiveness of microbial larvicides on mosquito larvae in malaria areas of Botswana and Zimbabween_ZA
dc.typeArticleen_ZA

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