n African Entomology - Species composition and biting activities of anthropophilic Anopheles mosquitoes and their role in malaria transmission in a holo-endemic area of southwestern Nigeria
|Article Title||Species composition and biting activities of anthropophilic Anopheles mosquitoes and their role in malaria transmission in a holo-endemic area of southwestern Nigeria|
|© Publisher:||Entomological Society of South Africa (ESSA)|
|Author||T.S. Awolola, K. Ibrahim, T. Okorie, L.L. Koekemoer, R.H. Hunt and M. Coetzee|
|Publication Date||Sep 2003|
|Pages||227 - 232|
|Keyword(s)||Anopheles arabiensis, Anopheles funestus, Anopheles gambiae, Anopheles hancocki, Anopheles mosquitoes, ELISA, Nigeria, PCR and Sporozoite rates|
The species composition of indoor and outdoor human-biting Anopheles mosquitoes and their relative contribution to Plasmodium falciparum transmission were determined for two communities in Ibadan, southwestern Nigeria where little or no data were available. Mosquitoes attracted to humans at night were caught in August, September and October 2000, coinciding with the peak malaria period in these areas. A total of 2176 Anopheles mosquitoes were collected, of which An. gambiae s.l. was predominant followed by An. Funestus and An. Hancocki. The results of PCR-based tests identified 58.8 % of the An. gambiae s.l. as An. gambiae s.s., and 41.2% as An. Arabiensis. The molecular (M and S) forms of An. gambiae s.s. were found in the ratio 1:3, respectively. A cocktail PCR-assay differentiated 65.6% of the An. Funestus group as An. funestus s.s., and 34.4% as An. Rivulorum. Outdoor biting mosquito numbers were significantly higher (P < 0.001) than that observed indoors. Peak indoor and outdoor biting activities of An. gambiae s.s. occurred at 01:00 and 24:00, respectively. The biting activities of An. funestus s.s. both indoors and outdoors attained a peak at 23h00 while An. Arabiensis and An. Rivulorum were more exophagic. The results of ELISA-based analyses indicated that An. gambiae s.s., An. Arabiensis and An. funestus s.s. serve as vectors in the area with an overall P. falciparum sporozoite infection rate of 5.6 %, 4.0% and 4.3 %, respectively. Both An. Rivulorum and An. Hancocki tested negative. The combined contribution of these mosquito species to malaria transmission in the study area highlights the inappropriateness of vector control strategies aimed at only one vector species.
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