Rapid detection and characterization of Chikungunya virus by RT-PCR in febrile patients from Kerala, India.

There has been a resurgence and prevalence of fever with symptoms of Chikungunya (CHIK) and increased death toll in Kerala, the southern-most state of India. The objective of this study was to develop a rapid detection method to determine the presence of CHIK- virus in the serum samples collected from febrile patients in Kerala, India. Serum specimens were analyzed for CHIK viral RNA by RT-PCR using primers specific for nsP1 and E1 genes. Five out of twenty clinical samples were positive for CHIK virus. The partial sequences of the E1 and nsP1 genes of the strain, IndKL01 were highly similar to the Reunion strains and the recently isolated Indian strains. A novel substitution, A148V, was detected in the E1 gene of the isolate, IndKL02. The detection procedure used in this study was simple, sensitive and rapid (less than 4 hr). This result suggests that CHIK viruses similar to the Reunion strains, which had resulted in high morbidity and mortality rates, may have caused the recent Chikungunya outbreak in India. The effect of the variant, E1-A148V, in the virulence and the rate of transmission of the virus deserves further investigation.