Infectious clones of Chikungunya virus (La Réunion isolate) for vector competence studies

The recent outbreak of Chikungunya virus (CHIKV) on several islands in the Indian Ocean and in India has focused attention on this reemerging virus and highlighted the need for development of new tools to study vector-virus-host interactions. We have constructed and characterized, in cell culture, Aedes aegypti and Ae. albopictus mosquitoes, infectious cDNA clones of CHIKV using a recent isolate from La Réunion Island. Comparison of the growth kinetics and infection rates of the viral isolate CHIKV strain LR2006 OPY1 (CHIKV-LR) and a full-length infectious clone (CHIKV-LR ic) indicate that the infectious clone has retained the viral phenotypes of the original isolate. Infectious clones that express green fluorescent protein (GFP) were also produced and characterized in cell culture and in Aedes mosquitoes. The CHIKV-LR 5'GFP infected Ae. aegypti and Ae. albopictus mosquitoes at a similar rate to the original virus and to the full length infectious clone. The CHIKV-LR 3'GFP only infected Ae. albopictus mosquitoes at similar rates. The development of these authentic infectious clones will enable targeted studies of the molecular determinants of infection, pathogenesis and transmission competence by Ae. aegypti and Ae. albopictus mosquitoes.