1921
Volume 77, Issue 4
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645

Abstract

In high-elevation areas in western Kenya, the abundance of is either very low or absent. The western Kenya highlands (an area with an elevation > 1,500m above sea level) have also been experiencing extensive deforestation, and deforestation has been suggested as one of the important factors that facilitate malaria transmission in the highlands. This study investigated whether climate conditions in the western Kenya highlands (Kakamega, elevation 1,500 m above sea level) were permissive to the development and survival of and whether deforestation promoted survivorship of immature and adult stages, using life-table analysis. We found that in larval habitats located in forested areas, only 4–9% of first-instar larvae developed into adults and the development length exceeded 20 days. Mean water temperature of aquatic habitats in the deforested area was 4.8–6.1°C higher than that in the forested area, larval-to-adult survivorship was increased to 65–82%, and larval-to-adult development time was shortened by 8–9 days. The average indoor temperature in houses in the deforested area was 1.7–1.8°C higher than in the forested area, and the relative humidity was 22–25% lower. The median survival time of adult mosquitoes in the deforested area was 49–55% higher than those in the forested area. The net reproductive rate of female mosquitoes in the deforested area was 1.7- to 2.6-fold higher than that in the forested area. Compared with previously published data on , the net reproductive rate of was only 0.8–1.3% of in the forested area and 2.3–2.6% in the deforested area. Therefore, the current ambient climate condition is less permissive to than to in western Kenya highlands. However, environmental changes such as deforestation and global warming may facilitate the establishment of populations in the highlands.

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  • Received : 26 Sep 2006
  • Accepted : 05 Jun 2007

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