Phylogenetic analysis of Indian serotype Asia1 foot-and-mouth-disease virus isolates revealed emergence and reemergence of different genetic lineages.

Foot-and-mouth-disease virus (FMDV) serotype Asia1 causes significant number of disease outbreaks in India. Indian Asia1 virus isolates were shown to be genetically heterogeneous and of the two lineages (lineage B and lineage C) described in India, lineage C caused majority of the outbreaks. Emergence of a novel divergent lineage (lineage D) within lineage C has been described in 2001. In the present report, the complete VP1 genomic region of 41 FMDV Asia1 field isolates collected between 2003 and 2008 was sequenced. Phylogenetic analysis revealed reemergence of lineage C since 2005 following exclusive dominance of lineage D in the period between 2002 and 2004. At many positions lineage specific signature residues were identified. The antigenic relationship of the field isolates with the currently used vaccine strain IND63/72 was also determined, which reflects antigenic stability of serotype Asia1 in-spite of genetic heterogeneity.