Estimation du risque d'introduction du virus de la fièvre de la vallée du Rift en Tunisie par le moustique Culex pipiens Assessment of the risk of introduction to Tunisia of the Rift Valley fever virus by the mosquito Culex pipiens

The mosquito Culex pipiens has been involved as vector of the West Nile virus in Tunisia. Its bio-ecological characteristics in combination with some environmental factors have favoured the emergence of this virus in a WestNile free zone. This leads to question about the potential risk of introducing another arbovirus, the Rift Valley fever (RVF) virus, in Tunisia from neighbouring countries where RVF circulates. In this study, we have evaluated the vector competence of different populations of Cx. pipiens towards two strains of RVF virus, the virulent ZH548 and the avirulent Clone 13 by experimental infections and the genetic differentiation of these populations of Cx. pipiens using four microsatellite loci. We found disseminated infection rates ranging from 0% to 14.7% and a high genetic differentiation among populations without any geographical pattern (no isolation by distance). Thus, although Cx. pipiens is able to sustain an amplification of RVF virus, viral dissemination through mosquito dispersal would be unlikely. However, as RVF is an emerging disease transmitted by several other potential mosquito species (e.g. Ochlerotatus caspius), attention should be maintained to survey livestock and mosquitoes in Tunisia. To cite this journal: Bull. Soc. Pathol. Exot. 104 (2011). G. Krida · A. Bouattour · A. Rhim Institut Pasteur de Tunis, service d’entomologie medicale, 13, Place Pasteur, BP 74, 1002 Tunis Belvedere, Tunisie G. Krida Institut national agronomique de Tunisie, 43, avenue Charles-Nicolle, 1082 Tunis Mahrajene, Tunisie L. Diancourt Institut Pasteur, plateforme genotypage des pathogenes et sante publique, 25–28, rue du Docteur-Roux, F-75724 Paris cedex 15, France B. Chermiti Institut superieur agronomique de Chott-Mariem, BP 47, 4042 Chott Meriem, Sousse, Tunisie A.-B. Failloux (*) Institut Pasteur, unite de genetique moleculaire des Bunyavirus, 25–28, rue du Docteur-Roux, F-75724 Paris cedex 15, France e-mail : anna-bella.failloux@pasteur.fr Bull. Soc. Pathol. Exot. (2011) 104:250-259 DOI 10.1007/s13149-010-0122-4