Surveillance of chikungunya virus in Andhra Pradesh,Southern India
摘要
Objective:The study involved survey and screening of areas suspected of chikungunya virus (CHIKV) infection,characterizing the causative agent and identifying the circulating CHIKV genotype.Methods:Acute phase samples were screened by the use of RTPCR using primer set DVRChk-F/DVRChk-R whereas convalescent samples were tested by CHIKV IgM strips. Results:Two hundred and seventy five acute phase samples were screened by RT-PCR.of which 149(54.18%) showed positivity for CHIKV.Later on 192 convalescent phase samples were tested for CHIKV specific antibodies in which 125(65.10%) samples were found to be positive.Four CHIKV strains were selected and subjected to cloning followed by nucleotide sequencing and were submitted to the Genbank DMA database with the Accession numbers(GQ119362,GQ119363, GQl 19364,and FJ225403).The Sequence analysis of 'CHIK-Kadapa' strain(GQ119362) with other CHIKV isolates suggested that the present CHIKV strain has(99.23±0.52)%and 100%identity with Central East South African isolates(CESA) at nucleotide and amino acid levels respectively.Two unique non synonymous mutations S168L and D183V were depicted in El gene of the selected strains of the present study.Conclusions:The 14 months survey revealed the circulation of CHIKV in 2008-2009 in Andhra Pradesh and the causative agent is identified to be of Central East South African(CESA) origin.The importance of the non synonymous mutations(S168L and D183V) and their role in the mobility and strength of the El-El and E1-E2 interactions needs further investigations.The study also urges the need for intensifying the epidemiological and entomological surveillance to combat any such CHIKV outbreak in the near future.