Does fluoride influence oviposition of Anopheles stephensi in stored water habitats in an urban setting?

Abstract

BackgroundThe physico-chemical characteristics of lentic aquatic habitats greatly influence mosquito species in selecting suitable oviposition sites; immature development, pupation and adult emergence, therefore are considerations for their preferred ecological niche. Correlating water quality parameters with mosquito breeding, as well as immature vector density, are useful for vector control operations in identifying and targeting potential breeding habitats.MethodsA total of 40 known habitats of Anopheles stephensi, randomly selected based on a vector survey in parallel, were inspected for the physical and chemical nature of the aquatic environment. Water samples were collected four times during 2013, representing four seasons (i.e., ten habitats per season). The physico-chemical variables and mosquito breeding were statistically analysed to find their correlation with immature density of An. stephensi and also co-inhabitation with other mosquito species.Results Anopheles stephensi prefer water with low nitrite content and high phosphate content. Parameters such as total dissolved solids, electrical conductivity, total hardness, chloride, fluoride and sulfate had a positive correlation in habitats with any mosquito species breeding (p < 0.05) and also in habitats with An. stephensi alone breeding. Fluoride was observed to have a strong positive correlation with immature density of An. stephensi in both overhead tanks and wells.ConclusionKnowledge of larval ecology of vector mosquitoes is a key factor in risk assessment and for implementing appropriate and sustainable vector control operations. The presence of fluoride in potential breeding habitats and a strong positive correlation with An. stephensi immature density is useful information, as fluoride can be considered an indicator/predictor of vector breeding. Effective larval source management can be focussed on specified habitats in vulnerable areas to reduce vector abundance and malaria transmission.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-016-1594-x) contains supplementary material, which is available to authorized users.

Combined effect of physico-chemical and microbial quality of breeding habitat water on oviposition of malarial vector Anopheles subpictus

“…Similar type of association was reported in An. stephensi mosquitoes from some rural and urban areas of West Bengal [64] although positive correlation was also documented in some areas of south-eastern Chennai [21].…”

“…[18,19]. Some of these parameters showed strong positive correlation with the larval abundance [20,21].…”

The Impact, Emerging Needs, and New Research Questions Arising from 12 Years of the Center for the Study of Complex Malaria in India

“… 6 , 7 We also found a strong positive correlation between the presence of fluoride and An. stephensi immature density in breeding habitats, 8 as well as detected malaria parasites in Anopheles subpictus , which was not previously considered a human malaria vector in Chennai. 7 Finally, we recently identified other factors such as roof type associated with the presence of An.…”

Advances in Basic and Translational Research as Part of the Center for the Study of Complex Malaria in India

“…stephensi immature density, an indicator/predictor of vector breeding. 30 Cattle sheds are the preferred resting place of An. stephensi , and dawn is the optimal time to collect and estimate its densities.…”