Molecular detection and characterization of African swine fever virus from field outbreaks in domestic pigs, Mizoram, India.

African swine fever (ASF) is a devastating haemorrhagic disease of domestic pigs, which can cause mortality up to 100%. Sudden mortality in pigs following an acute course of systemic disease was investigated in Mizoram state of India and confirmed the outbreak as ASF. Affected pigs suffered from severe depression, high fever, bloody diarrhoea, cutaneous haemorrhages and showed haemorrhagic lesions in visceral organs. The outbreak was confirmed by detection of p72, p54 and the central variable region of B602L genes by PCR in representative tissue samples collected from dead pigs. The nucleotide and phylogenetic analyses of p72, p54 and B602L characterized the ASFV as genotype II. Interestingly, the analysis of B602L gene has revealed that the ASFV from Mizoram state of India is more closely linked to the Eurasian ASFV strains isolated prior to 2014 and discriminated the Indian strains in two separate groups indicating that the source of origin for the Mizoram outbreak could be different from that of the other states of India.