SUMMARY The Chikungunya virus (CHIKV) is a mosquito-borne Alphavirus, which causes epidemics of fever, rash and polyarthralgia in Africa and Asia. First isolated in 1953 in Tanzania, CHIKV has caused numerous well-documented outbreaks and epidemics in both Africa and South-East Asia. The epidemic of Chikungunya fever that affected the population of La Reunion at Christmas in 2005 will be remembered as the most serious public health crises in the island's history. A widely circulating mutant CHIKV is a possible explanation for the epidemiological pattern of the disease in this region. In this review, we have tried to give the latest information about the present outbreak and have tried to analyse the possible reasons for the same.