JLE

Environnement, Risques & Santé

MENU

Relations between rain patterns and risk of virus transmission by mosquitoes: Rift Valley Fever (RVF) virus in the Ferlo region of Senegal. Volume 4, issue 2, Mars-Avril 2005

Figures

See all figures

Authors
Institut de recherche pour le développement (IRD), UR 34 « Maladies virales émergentes et systèmes d’information », BP 1386, Dakar, Sénégal, Institut sénégalais de recherches agricoles (ISRA), Laboratoire national de l’élevage et de recherches vétérinaires (ISRA-LNERV), BP 2057, Dakar-Hann, Sénégal, Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), département élevage et médecine vétérinaire (CIRAD-Emvt), Campus international de Baillarguet, 34398 Montpellier cedex 05, France

A two-year follow-up study in the Ferlo region in Senegal examined the importance of rainfall episodes on the development of two populations of potential vectors of Rift Valley fever in West Africa: Aedes vexans arabiensis and Culex poicilipes. Rainy seasons sometimes begin, as in 2003, with heavy rains, and temporary ponds are immediately flooded at their maximum level. In these conditions, Aedes populations are numerous at the beginning of the season, when this flooding hatches the maximum number of dormant eggs. Culex populations multiply only a month after the flooding of the ponds. Risk of virus transmission by the Aedes is thus higher in the first half of the rainy season. If there are substantial rains at the end of the season, the magnitude of the risks from the Culex depends on the duration of the flooding.