Molecular epidemiology of Chikungunya virus: mutation in E1 gene region.

Chikungunya virus is a mosquito-transmitted RNA virus and emerging as a pathogen that has a major public health impact because of the high morbidity including high fever, headache, rash, nausea, vomiting, myalgia, arthralgia with or without neurological manifestation or fulminant hepatitis. One hundred fifty-one patient samples were analyzed during the years 2006-2008, and compared conventional tests and CCRT-PCR (cell culture RT PCR). The conventional tests included ELISA, inoculation into C6/36 cell line and CPE were examined by PCR after RNA extraction. A total of 20/151 (13.2%), 8/151 (5.29%) and 7/151 (4.6%) samples were found to be positive by ELISA, cell culture and PCR, respectively. While 7/20 (35%) of the samples were positive by CCRT_PCR when ELISA 20 positive samples were detected. A total of 5/7 positive strains were sequenced in the E1 gene region. Remarkable changes (M269V, D284E, P294L, S295F, A316V, V322A, and C328W) were observed in the membrane fusion glycoprotein E1. These unique molecular features of the isolates with the continuing epidemic demonstrated high evolutionary potential and thereby indicating higher virulence.