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



A 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.



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.



Knowledge 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.
IDVC Field Unit, National Institute of Malaria Research (ICMR), NIE Campus, 2nd Main Road, TNHB, Ayapakkam, Chennai, 600 077, India.
Shalu
S
Thomas
IDVC Field Unit, National Institute of Malaria Research (ICMR), NIE Campus, 2nd Main Road, TNHB, Ayapakkam, Chennai, 600 077, India.
Sangamithra
S
Ravishankaran
IDVC Field Unit, National Institute of Malaria Research (ICMR), NIE Campus, 2nd Main Road, TNHB, Ayapakkam, Chennai, 600 077, India.
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Johnson Amala Justin
IDVC Field Unit, National Institute of Malaria Research (ICMR), NIE Campus, 2nd Main Road, TNHB, Ayapakkam, Chennai, 600 077, India.
Aswin
A
Asokan
IDVC Field Unit, National Institute of Malaria Research (ICMR), NIE Campus, 2nd Main Road, TNHB, Ayapakkam, Chennai, 600 077, India.
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T
Maria Jusler Kalsingh
Department of Zoology, Madras Christian College, Tambaram, Chennai, 600 059, India.
Manu Thomas
MT
Mathai
National Institute of Malaria Research (ICMR), Sector 8, Dwarka, New Delhi, 110 077, India.
Neena
N
Valecha
IDVC Field Unit, National Institute of Malaria Research (ICMR), NIE Campus, 2nd Main Road, TNHB, Ayapakkam, Chennai, 600 077, India. alexeapen@yahoo.com.
Alex
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Eapen
D000818:Animals; D000852:Anopheles / Q000187:drug effects* / Q000254:growth & development* / Q000502:physiology; D055598:Chemical Phenomena; D017753:Ecosystem; D005260:Female; D005459:Fluorides / Q000378:metabolism*; D010058:Oviposition / Q000187:drug effects*; D014867:Water / Q000737:chemistry*
D014867:Water; D005459:Fluorides
Anopheles stephensi; Breeding habitats; Fluoride; Physico-chemical factors