Aquatic habitats of the malaria vector Anopheles funestus in rural south-eastern Tanzania

Nambunga, I. H. et al. (2020) Aquatic habitats of the malaria vector Anopheles funestus in rural south-eastern Tanzania. Malaria Journal, 19, 219. (doi: 10.1186/s12936-020-03295-5) (PMID:32576200) (PMCID:PMC7310514)

Abstract

Background: In rural south-eastern Tanzania, Anopheles funestus is a major malaria vector, and has been implicated in nearly 90% of all infective bites. Unfortunately, little is known about the natural ecological requirements and survival strategies of this mosquito species. Methods: Potential mosquito aquatic habitats were systematically searched along 1000 m transects from the centres of six villages in south-eastern Tanzania. All water bodies were geo-referenced, characterized and examined for presence of Anopheles larvae using standard 350 mLs dippers or 10 L buckets. Larvae were collected for rearing, and the emergent adults identified to confirm habitats containing An. funestus. Results: One hundred and eleven habitats were identified and assessed from the first five villages (all < 300 m altitude). Of these, 36 (32.4%) had An. funestus co-occurring with other mosquito species. Another 47 (42.3%) had other Anopheles species and/or culicines, but not An. funestus, and 28 (25.2%) had no mosquitoes. There were three main habitat types occupied by An. funestus, namely: (a) small spring-fed pools with well-defined perimeters (36.1%), (b) medium-sized natural ponds retaining water most of the year (16.7%), and (c) slow-moving waters along river tributaries (47.2%). The habitats generally had clear waters with emergent surface vegetation, depths > 0.5 m and distances < 100 m from human dwellings. They were permanent or semi-permanent, retaining water most of the year. Water temperatures ranged from 25.2 to 28.8 °C, pH from 6.5 to 6.7, turbidity from 26.6 to 54.8 NTU and total dissolved solids from 60.5 to 80.3 mg/L. In the sixth village (altitude > 400 m), very high densities of An. funestus were found along rivers with slow-moving clear waters and emergent vegetation. Conclusion: This study has documented the diversity and key characteristics of aquatic habitats of An. funestus across villages in south-eastern Tanzania, and will form an important basis for further studies to improve malaria control. The observations suggest that An. funestus habitats in the area can indeed be described as fixed, few and findable based on their unique characteristics. Future studies should investigate the potential of targeting these habitats with larviciding or larval source management to complement malaria control efforts in areas dominated by this vector species.

• Item Type: Articles
• Additional Information: The activities in this work were supported by Howard Hughes Medical Institute (HHMI)—Gates International Research Scholar Award to FO at Ifakara Health Institute (OPP1175877) and Bill & Melinda Gates Foundation Grant, also to Ifakara Health Institute (OPP1177156).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Ngowo, Halfan and Okumu, Professor Fredros
• Authors: Nambunga, I. H., Ngowo, H. S., Mapua, S. A., Hape, E. E., Msugupakulya, B. J., Msaky, D. S., Mhumbira, N. T., Mchwembo, K. R., Tamayamali, G. Z., Mlembe, S. V., Njalambaha, R. M., Lwetoijera, D. W., Finda, M. F., Govella, N. J., Matoke-Muhia, D., Kaindoa, E. W., and Okumu, F. O.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Malaria Journal
• Publisher: BioMed Central
• ISSN: 1475-2875
• ISSN (Online): 1475-2875
• Copyright Holders: Copyright © 2020 The Authors
• First Published: First published in Malaria Journal 19: 219
• Publisher Policy: Reproduced under a Creative Commons License