Chikungunya outbreak in Montpellier, France, September to October 2014.

In October 2014, an outbreak of 12 autochthonous chikungunya cases, 11 confirmed and 1 probable, was detected in a district of Montpellier, a town in the south of France colonised by the vector Aedes albopictus since 2010. A case returning from Cameroon living in the affected district was identified as the primary case. The epidemiological investigations and the repeated vector control treatments performed in the area and around places frequented by cases helped to contain the outbreak. In 2014, the chikungunya and dengue surveillance system in mainland France was challenged by numerous imported cases due to the chikungunya epidemic ongoing in the Caribbean Islands. This first significant outbreak of chikungunya in Europe since the 2007 Italian epidemic, however, was due to an East Central South African (ECSA) strain, imported by a traveller returning from West Africa. Important lessons were learned from this episode, which reminds us that the threat of a chikungunya epidemic in southern Europe is real.

A multiplex PCR to differentiate the two sibling species of mosquitoes Ochlerotatus detritus and Oc. coluzzii and evidence for further genetic heterogeneity within the Detritus complex.

Internal transcribed spacer regions of ribosomal DNA were sequenced, and species-specific primers were designed to simplify the identification of two morphologically similar species of the Detritus complex, Ochlerotatus detritus and Ochlerotatuscoluzzii. Each newly designed primer was able to amplify a species-specific fragment with a different size. Samples from France and Germany were successfully tested. This new tool prompts for bio-ecological studies to refine basic knowledge on the bionomics of this species complex, towards a better control and prevention of ensuing nuisances. Moreover, ITS2 sequencing revealed the existence of (1) two distinct haplotypes of Oc. detritus that are sympatric and widely distributed along the French Atlantic and Mediterranean littorals and (2) a specific haplotype in mosquitoes sampled from Tunisia, raising the question of the taxonomic status of this North-African population.