Canine parvovirus in North-East India: a phylogenetic and evolutionary analysis.

Canine parvovirus type 2 (CPV-2) infection in dogs is considered as one of the most common cause of morbidity and mortality in young dogs and continues to occur with high incidence worldwide. Despite a single-stranded DNA virus, CPV-2 possesses a high mutation rate which has led to the development of new variants from time to time. These variants are classically classified based on the amino acid markers present in the VP2 gene. In this study, we examined 20 different cases of CPV-2 infection from seven different states of the North East region (NER) of India. The near-complete genome sequences of all these isolates were subjected to phylodynamic and phylogeographic analysis to evaluate the genetic diversity and geographical spread of CPV-2 variants. Analysis of the deduced amino acid sequences revealed residues characteristic of the 'Asian CPV-2c lineage' in all the 20 sequences confirming it as the dominant strain circulating in NER, India. The phylogenetic analysis based on the whole genome showed that all 20 sequences formed a monophyletic clade together with other Asian CPV-2c sequences. Furthermore, phylogeographic analysis based on the VP2 gene showed the likely introduction of Asian CPV-2c strain to India from China. This study marks the first comprehensive report elucidating the molecular epidemiology of CPV-2 in India.