Increase in dengue fever imported from Côte d’Ivoire and West Africa to France.

Dengue is usually not considered a significant health problem in Africa because severe forms of dengue illness are rarely reported. In the absence of local surveillance data, the investigation of dengue cases imported to France contributed to document the circulation of dengue virus in this area. From 1 July 2006 to 31 December 2008, a total of 148 dengue cases imported to metropolitan France were reported through the mandatory notification system. Arthralgia and signs of severity (haemorrhage, thrombocytopenia) were less frequent in patients returning from West African countries. DENV-3 was isolated in two patients from Côte d’Ivoire in 2008. The number and proportion of patients returning from Côte d’Ivoire to France increased significantly in 2008 compared with the previous 18-month period. In parallel, the marginal increase in air travel does not explain the high increase observed in imported dengue cases to France. Our data illustrate increased dengue circulation and the emergence of DENV-3 in this area, with public health implications for epidemiological surveillance and case management locally.