Emerging infection of swinepox in the pig population of Assam

Swinepox is a mild, acute disease of swine characterised by typical poxviral lesions of the skin caused by swinepox virus (SWPV), a member of the genus Suipoxvirus of the family Poxviridae.India is endemic for poxvirus infection. A total of ten natural outbreaks of suspected swinepox infection affecting pig population of Assam were investigated. Clinical lesions in the affected pigs were characterised by formation of typical pox lesion, progressing through the classic stages of macule, papule and pustule or crust formation. Scab samples (n=71) were collected from affected pigs. The disease was diagnosed based on clinical sign, electron microscopy (EM) and molecular methods. The samples were screened for presence of SWPV antigen by amplification of three swinepox specific genes, viz., SPV 18–20 gene, VLTF-3 gene and P42 gene in PCR. Out of 71 samples screened, 36 (50–70%) were found positive for all three genes. On agarose gel electrophoresis, clear expected band sizes of 555bp, 524 bp and 880 bp could be observed corresponding to the SPV 18–20 gene, VLTF-3 gene and P42 gene, respectively. Samples were collected from only three districts of Assam, viz., Kamrup, Lakhimpur and Karbi Anglong, of which Karbi Anglong district showed the highest percent positivity (55.55%) followed by Lakhimpur (50.00%) and Kamrup (35.71%). Assam and the other north-eastern states of India being a hub for pig husbandry, it is high time to concentrate on developing and formulating control strategies for this emerging infection.