Chikungunya virus was isolated in Thailand, 2010

Chikungunya fever (CHIKF) is an acute febrile illness caused by a mosquito-borne alphavirus, chikungunya virus (CHIKV). This disease re-emerged in Kenya in 2004, and spread to the countries in and around the Indian Ocean. The re-emerging epidemics rapidly spread to regions like India and Southeast Asia, and it was subsequently identified in Europe in 2007, probably as a result of importation of chikungunya cases. On the one hand, chikungunya is one of the neglected diseases and has only attracted strong attention during large outbreaks. In 2008-2009, there was a major outbreak of chikungunya fever in Thailand, resulting in the highest number of infections in any country in the region. However, no update of CHIKV circulating in Thailand has been published since 2009. In this study, we examined the viral growth kinetics and sequences of the structural genes derived from CHIKV clinical isolates obtained from the serum specimens of CHIKF-suspected patients in Central Thailand in 2010. We identified the CHIKV harboring two mutations E1-A226V and E2-I211T, indicating that the East, Central, and South African lineage of CHIKV was continuously circulating as an indigenous population in Thailand.