Microevolutionary trends of dengue virus-3 in Kerala, India.

Envelope gene is of great evolutionary significance and had been targeted as the vaccine candidate for dengue virus. We analyzed partial sequences of this gene to understand its genetic variability among viral isolates from Kerala state, India, if any. The current study focused on the evolutionary trends of this phylogenetically important gene among DENV-3 isolates through 2008 to 2010 outbreaks. The results gave an insight into the microevolutionary trends of the dengue viral genome. A unique mutation was recorded in the Domain II of the Envelope gene (EDII) of the viral genome at the amino acid position 219 (A219T). The evolutionary implication of this non-synonymous mutation near the EDI/EDII hinge remains to be explored. The study also provided knowledge on the genetic ancestral history of the viral isolates. Two variants of different phylogenetic origin were recorded in Kerala State. The findings in the study have significant implications on the development of dengue vaccines based on the Envelope gene of the virus.