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

BACKGROUND: Highland 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 c...

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Autores principales: Tchuinkam, Timoléon, Simard, Frédéric, Lélé-Defo, Espérance, Téné-Fossog, Billy, Tateng-Ngouateu, Aimé, Antonio-Nkondjio, Christophe, Mpoame, Mbida, Toto, Jean-Claude, Njiné, Thomas, Fontenille, Didier, Awono-Ambéné, Herman-Parfait
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2889998/
https://www.ncbi.nlm.nih.gov/pubmed/20482824
http://dx.doi.org/10.1186/1471-2334-10-119
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author Tchuinkam, Timoléon
Simard, Frédéric
Lélé-Defo, Espérance
Téné-Fossog, Billy
Tateng-Ngouateu, Aimé
Antonio-Nkondjio, Christophe
Mpoame, Mbida
Toto, Jean-Claude
Njiné, Thomas
Fontenille, Didier
Awono-Ambéné, Herman-Parfait
author_facet Tchuinkam, Timoléon
Simard, Frédéric
Lélé-Defo, Espérance
Téné-Fossog, Billy
Tateng-Ngouateu, Aimé
Antonio-Nkondjio, Christophe
Mpoame, Mbida
Toto, Jean-Claude
Njiné, Thomas
Fontenille, Didier
Awono-Ambéné, Herman-Parfait
author_sort Tchuinkam, Timoléon
collection PubMed
description BACKGROUND: Highland 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. METHODS: Longitudinal 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. RESULTS: Anopheline 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. CONCLUSION: Malaria 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.
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spelling pubmed-28899982010-06-23 Bionomics of Anopheline species and malaria transmission dynamics along an altitudinal transect in Western Cameroon Tchuinkam, Timoléon Simard, Frédéric Lélé-Defo, Espérance Téné-Fossog, Billy Tateng-Ngouateu, Aimé Antonio-Nkondjio, Christophe Mpoame, Mbida Toto, Jean-Claude Njiné, Thomas Fontenille, Didier Awono-Ambéné, Herman-Parfait BMC Infect Dis Research Article BACKGROUND: Highland 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. METHODS: Longitudinal 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. RESULTS: Anopheline 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. CONCLUSION: Malaria 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. BioMed Central 2010-05-19 /pmc/articles/PMC2889998/ /pubmed/20482824 http://dx.doi.org/10.1186/1471-2334-10-119 Text en Copyright ©2010 Tchuinkam et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
Tchuinkam, Timoléon
Simard, Frédéric
Lélé-Defo, Espérance
Téné-Fossog, Billy
Tateng-Ngouateu, Aimé
Antonio-Nkondjio, Christophe
Mpoame, Mbida
Toto, Jean-Claude
Njiné, Thomas
Fontenille, Didier
Awono-Ambéné, Herman-Parfait
Bionomics of Anopheline species and malaria transmission dynamics along an altitudinal transect in Western Cameroon
title Bionomics of Anopheline species and malaria transmission dynamics along an altitudinal transect in Western Cameroon
title_full Bionomics of Anopheline species and malaria transmission dynamics along an altitudinal transect in Western Cameroon
title_fullStr Bionomics of Anopheline species and malaria transmission dynamics along an altitudinal transect in Western Cameroon
title_full_unstemmed Bionomics of Anopheline species and malaria transmission dynamics along an altitudinal transect in Western Cameroon
title_short Bionomics of Anopheline species and malaria transmission dynamics along an altitudinal transect in Western Cameroon
title_sort bionomics of anopheline species and malaria transmission dynamics along an altitudinal transect in western cameroon
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2889998/
https://www.ncbi.nlm.nih.gov/pubmed/20482824
http://dx.doi.org/10.1186/1471-2334-10-119
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