V Chevalier1, M Pépin2, L Plée3, R Lancelot4
1 Centre International de Recherche Agronomique pour le Développement (CIRAD, International Centre of Agricultural Research for Development), Unit for animal and integrated risk management (UR AGIRs), Montpellier, France
2 Agence française pour la sécurité sanitaire des aliments (AFSSA, French Agency for Food Safety), Lyon, France
3 Agence française pour la sécurité sanitaire des aliments (AFSSA, French Agency for Food Safety), Unit for the evaluation of
risks associated with food and animal health, Maisons-Alfort, France
4 Centre International de Recherche Agronomique pour le Développement (CIRAD, International Centre of Agricultural Research for Development), Unit for the control of exotic and emerging animal diseases (UMR CMAEE), Montpellier, France
Eurosurveillance, March 2010, 15(10):pii=19506, 18-28

Rift Valley fever (RVF) is a severe mosquito-borne disease affecting humans and domestic ruminants, caused by a Phlebovirus (Bunyaviridae). It is widespread in Africa and has recently spread to Yemen and Saudi Arabia. RVF epidemics are more and more frequent in Africa and the Middle East, probably in relation with climate changes (episodes of heavy rainfall in eastern and southern Africa), as well as intensified livestock trade. The probability of introduction and large-scale spread of RVF in Europe is very low, but localised RVF outbreaks may occur in humid areas with a large population of ruminants. Should this happen, human cases would probably occur in exposed individuals: farmers, veterinarians, slaughterhouse employees etc. Surveillance and diagnostic methods are available but control tools are limited: vector control is difficult to implement, and vaccines are only available for ruminants, with either a limited efficacy (inactivated vaccines) or a residual pathogenic effect. The best strategy to protect Europe and the rest of the world against RVF is to develop more efficient surveillance and control tools and to implement coordinated regional monitoring and control programmes.

Link to the article: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19506

VBORNET comment: 2010-05-27
This paper provides a comprehensive review and risk assessment of the potential for RVFV introduction and outbreaks in Europe, although it provides little new information on the ecological and entomological dynamics of such RVFV outbreaks should they occur in Europe. More than 30 mosquito species globally have been found infected with RVFV including species in 7 genera: Aedes, Ochlerotatus, Anopheles, Culex, Eretmapodites, Coquillettidia and Mansonia. In Europe the main competent vectors are Aedes vexans vexans, Oc. caspius, Cx. theileri, Cx. pipiens and Cx. perexiguus. They conclude that Cx. pipiens and possibly Ae. albopictus would be the main candidate vectors. Additional summaries and discussion are given on the clinical features of RVFV (in animal and humans), diagnostic methods, vaccines, current geographic distribution and factors for change. They conclude that the greatest risk to Europe is likely to come from illegally imported RVFV-infected ruminants.