Effect of swamp cultivation on distribution of anopheline larval habitats in western kenya
Elizabeth Omukunda1, Andrew Githeko2, Millicent F Ndong'a3, Emmanuel Mushinzimana4, Guiyun Yan5
1 Climate and Human Health Unit, Medical Research Institute, Centre for Vector Biology and Control Research, Kisumu; Department of Zoology, Maseno University; Masinde Muliro University of Science and Technology, Kakamega, Kenya
2 Climate and Human Health Unit, Medical Research Institute, Centre for Vector Biology and Control Research, Kisumu, Kenya
3 Department of Zoology, Maseno University, Kenya
4 Climate and Human Health Unit, Medical Research Institute, Centre for Vector Biology and Control Research, Kisumu, ; Department of Biological Sciences, State University of New York, Buffalo, New York, USA, Kenya
5 Department of Biological Sciences, State University of New York, Buffalo, New York, USA
Climate and Human Health Unit, Kenya Medical Research Institute, Centre for Vector Biology and Control Research, Kisumu
Source of Support: None, Conflict of Interest: None
Background & objectives: Malaria resurgence in highland regions of East Africa has been on increase. The spatio-temporal distribution of larval habitats of malaria vectors determines the distribution of adult vectors, hence, disease transmission. Vector's ecology is necessary for strategic vector control through effective plan for source reduction. Mapping of the larval habitats is necessary for targeted control measures. The purpose of this study is to assess and compare the spatial and seasonal variations in anopheline larval habitats in Western Kenya.
Methods: A comparative study was conducted on spatial distribution of GPS geo-located anopheline larval habitats in relation to highland and lowland environments. Land use types were categorized and all potential aquatic habitats of malaria vectors were examined in February, May, August and November 2004. Data analyses were performed using SAS JMP software.
Results & discussion: Results showed a higher percentage of Anopheles gambiae s.s. (70.9%) than An. funestus (29.1%) in highland. In the lowland, An. gambiae s.l. comprised 60.1% while An. funestus represented 39.9%. The distribution of larval breeding is confined to the valley bottom in the highland while it was dispersed in the lowland. Land use type influenced the occurrence of positive breeding habitats in the highland. In the lowland, distribution was due to seasonality. We found high proportion of potential and positive breeding sites in cultivated swamps and farmlands at the highland site. These results suggest that swamp cultivation increases the availability and suitability of larval breeding habitats of malaria vectors, thus malaria transmission in the Western Kenya highlands environment.