Identification of a novel cluster of PCV2 isolates from Meghalaya, India indicates possible recombination along with changes in capsid protein.

Abstract

Documentation of the emergence of Porcine circovirus 2 (PCV2) infection and economic losses incurred due to high mortality has been reported worldwide. The prevalence and genetic diversity of the virus has been reported in Northeast India including the possible chances of Classical swine fever virus (CSFV) vaccine failure in pig population in this region resulting in major disease outbreak. Irrespective of the genetic variability, the emergence of a novel cluster (based on the ORF2 phylogeny) was reported last year. The present study describes a state-wide (Meghalaya, India) molecular epidemiological investigation of PCV2 strains in pig population by amplification, sequencing and undertaking phylogenetic analyses. The results indicate the identification of a novel cluster of PCV2 originating from the inter-genotypic recombination between PCV2c and PCV2d. Multiple sequence alignment of amino acids indicates possible substitution in the A, B and C domains of the capsid protein. Molecular structural modelling of the capsid protein of PCV2 indicated possible motif variations in the secondary structure including presence of a tunnel, encountered at the interface region on each chain facilitating in transportation of molecules and acting as an active site for attachment and penetration. The baseline data strengthens the existing control programme of PCV2 and is possibly helpful in the planning of active surveillance strategy in this region.