Bionomics of Anopheline species and malaria transmission dynamics along an altitudinal transect in Western Cameroon

BMC Infectious Diseases

Research Article

Billy Téné-Fossog¹  Thomas Njiné¹  Didier Fontenille²  Jean-Claude Toto³  Christophe Antonio-Nkondjio³  Herman-Parfait Awono-Ambéné³  Frédéric Simard⁴  Aimé Tateng-Ngouateu⁵  Mbida Mpoame⁵  Espérance Lélé-Defo⁵  Timoléon Tchuinkam⁶ 

[1] Hydrobiology laboratory, Faculty of Sciences of the University of Yaounde I, PO Box 812, Yaounde, Cameroon;Laboratoire de Lutte contre les Insectes Nuisibles (LIN-UR 016), Institut de Recherche pour le Développement (IRD), BP 64501, 911 Av Agropolis, 34394, Montpellier, France;Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), BP 288, Yaoundé, Cameroon;Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), BP 288, Yaoundé, Cameroon;Laboratoire de Lutte contre les Insectes Nuisibles (LIN-UR 016), Institut de Recherche pour le Développement (IRD), BP 64501, 911 Av Agropolis, 34394, Montpellier, France;Laboratory of Applied Biology and Ecology (LABEA), Department of Animal Biology, Faculty of Sciences of the University of Dschang, PO Box 067, Dschang, Cameroon;Laboratory of Applied Biology and Ecology (LABEA), Department of Animal Biology, Faculty of Sciences of the University of Dschang, PO Box 067, Dschang, Cameroon;Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), BP 288, Yaoundé, Cameroon;

关键词: Malaria;    Malaria Transmission;    Entomological Inoculation Rate;    Human Landing Catch;    Gonotrophic Cycle;   

DOI  :  10.1186/1471-2334-10-119

 received in 2009-10-06, accepted in 2010-05-19,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundHighland areas of Africa are mostly malaria hypoendemic, due to climate which is not appropriate for anophelines development and their reproductive fitness. In view of designing a malaria control strategy in Western Cameroon highlands, baseline data on anopheline species bionomics were collected.MethodsLongitudinal entomological surveys were conducted in three localities at different altitudinal levels. Mosquitoes were captured when landing on human volunteers and by pyrethrum spray catches. Sampled Anopheles were tested for the presence of Plasmodium circumsporozoite proteins and their blood meal origin with ELISA. Entomological parameters of malaria epidemiology were assessed using Mac Donald's formula.ResultsAnopheline species diversity and density decreased globally from lowland to highland. The most aggressive species along the altitudinal transect was Anopheles gambiae s.s. of S molecular form, followed in the lowland and on the plateau by An. funestus, but uphill by An. hancocki. An. gambiae and An. ziemanni exhibited similar seasonal biting patterns at the different levels, whereas different features were observed for An. funestus. Only indoor resting species could be captured uphill; it is therefore likely that endophilic behaviour is necessary for anophelines to climb above a certain threshold. Of the ten species collected along the transect, only An. gambiae and An. funestus were responsible for malaria transmission, with entomological inoculation rates (EIR) of 90.5, 62.8 and zero infective bites/human/year in the lowland, on the plateau and uphill respectively. The duration of gonotrophic cycle was consistently one day shorter for An. gambiae as compared to An. funestus at equal altitude. Altitudinal climate variations had no effect on the survivorship and the subsequent life expectancy of the adult stage of these malaria vectors, but most probably on aquatic stages. On the contrary increasing altitude significantly extended the duration of gonotrophic cycle and reduced: the EIR, their preference to human blood and consequently the malaria stability index.ConclusionMalaria epidemiological rooting in the outskirts of Western Cameroon highlands evolves with increasing altitude, gradually from stable to unstable settings. This suggests a potential risk of malaria epidemic in highlands, and the need for a continuous epidemiological surveillance.

【 授权许可】

CC BY   
© Tchuinkam et al; licensee BioMed Central Ltd. 2010