Influence of host and larval habitat distribution on the abundance of African malaria vectors in western Kenya.

Abstract

Abstract. The abundance of anopheline mosquitoes varies substantially among houses within the same villages. Anopheles gambiae sensu stricto is highly anthropophilic, and Anopheles arabiensis is zoophilic; thus, it is often hypothesized that the abundance of An. gambiae and An. arabiensis in a house is associated with the distribution of livestock and humans. In this paper we examined the influence of livestock and human host availability on the distribution and abundance of malaria vectors in the basin region of Lake Victoria in western Kenya. Larvae and adults of An. gambiae, An. arabiensis and Anopheles funestus were collected in the beginning and the end of the rainy season in 1999. Anopheles gambiae was the predominant species in both larval and adult samples. Multiple regression analyses found that the ratio of distance between houses and larval habitats to distance between cowsheds and larval habitats had a significant and negative association with the relative abundance of An. gambiae larvae for both sampling periods. The ratio of human density to cow density was positively correlated with the relative abundance of An. gambiae larvae in the late rainy period. For the adult samples, distance from a house to its nearest larval habitats was the only variable that showed a significant correlation with the An. gambiae density in houses in both sample periods. More than 90% of anopheline adults were found in the houses within 300 meters from the nearest larval habitats. Anopheline mosquito density was not correlated to the density of cows or humans, or the distance to cowsheds from houses. These results suggest that livestock and human host availability affect the relative abundance of An. gambiae larvae in aquatic habitats, but the distribution of anopheline adults in houses is determined by the distance from houses to larval habitats.

The Epidemiology of Malaria in Belize, 1989-1999

“…gambiae based on the distance of larval habitats to the closest house (Minakawa et al 1999, Minakawa et al 2002. Most of the Anopheles adults in that study were collected within houses that were less than 300 meters of the closest larval habitat.…”

Anopheline Mosquitoes and the Malaria Scourge

“…arabiensis, and An. funestus which are more dominant species during the dry periods [11,30]. The distance between oviposition site and blood host may affect the oviposition choice [17].…”

“…The distance between oviposition site and blood host may affect the oviposition choice [17]. [30] showed that immatures of An. gambiae would be found in breeding sites closer to houses and further away from cowsheds and a study [31] showed that significantly more larvae of An.…”

Environmental Determinants of Malaria Transmission Around the Koka Reservoir in Ethiopia

“…Closer proximity of a village to a reservoir is associated with higher number 10.1002/2017GH000108 of annual malaria cases because mosquitoes' lifetime flight distance limits malaria transmission far away from their breeding sites (Bomblies, 2014;Cano et al, 2006;Endo & Eltahir, 2016;Gu et al, 2006;Minakawa et al, 2002;Trape et al, 1992;van der Hoek et al, 2003;Zhou et al, 2007). For example, around the Koka Reservoir (N8 ∘ 25 ′ ; E39 ∘ 05 ′ ) in Ethiopia, the annual malaria case rates among people living within 1 km of the reservoir was 2.9 times greater than those living between 1 and 2 km from it, and 19.9 times greater than those living 5 to 9 km from it (Kibret et al, 2009).…”