Publications des agents du Cirad


Serological follow up of rift valley fever in a sahelian ecosystem 2004

Chevalier V., Thiongane Y., Etter E., Lancelot R.. 2007. In : Camus Emmanuel (ed.), Cardinale Eric (ed.), Dalibard Christophe (ed.), Martinez Dominique (ed.), Renard Jean-François (ed.), Roger François (ed.). Does control of animal infectious risks offer a new international perspective ? : proceedings of the 12th International Conference of the Association of Institutions of Tropical Veterinary Medicine, Montpellier, France, 20-22 August 2007. Montpellier : CIRAD, p. 107-111. International Conference of the Association of Institutions of Tropical Veterinary Medicine. 12, 2007-08-20/2007-08-22, Montpellier (France).

In 2003, a serological study performed in the Ferlo area (northern Senegal), showed that (i) Rift valley fever was endemic; (ii) the risk of transmission depended on the pond type (Chevalier, et al. 2005). In 2004, a serological longitudinal survey was undertaken in the same area. A total of 260 sheep were sampled three times: starting, middle and end of the rainy season. Sera were tested for anti-RVF immunoglobulin G (IgG) using a seroneutralization test. Statistical analyses were performed using a generalized linear model, with the incidence as the response and the period as the explanatory variable. The overall incidence rate was lower than in 2003 (1.7% vs 5.4%). The observed incidence rate was 3% (n= 166) from August till early October. It was 5.10-3 % (n = 177) from early October till the end of November. These results associated with entomological knowledge suggested that the main period of transmission is the middle of the rainy season. Ponds infected in 2003 remained infected in 2004. Rift Valley fever is endemic in this area but the way the virus is maintained in the field remains unknown. Assumptions on the persistence mechanisms are formulated. The relevance of vaccination is discussed.

Documents associés

Communication de congrès

Agents Cirad, auteurs de cette publication :