Phylogenetic analysis of Orf virus associated with contagious ecthyma (orf) outbreak in Tellicherry goats (Capra hircus)

Abstract

Orf virus (ORFV) is a member of genus Parapoxvirus that causes contagious ecthyma in goats. A pox-like disease was investigated in Tellicherry goats (31 female) maintained at a semi-organized farm. History revealed recent introduction of Tellicherry goats for breeding purpose and housing of the new entrants in to a farm already having a mild form of pox-like disease. Newly introduced and stressed Tellicherry goats developed severe form of infection with 100% morbidity. Affected goats showed lesions around lips (100%), commissure (53%) and oral cavity (65%); exanthematic dermatitis was evident in 94% of the affected goats followed by ulceration (47%) and nodular lesions (24%). Scab samples were collected from affected goats to confirm the clinical diagnosis. Genus Parapoxvirus was confirmed by the amplification of specific 594 bp and 235 bp amplicons. Further, Orf virus specific amplicon of size 1,206 bp was also amplified for the confirmation. Sequence analysis of PCR amplicons showed close resemblance of the outbreak strain with reported Indian Orf virus isolates. Based on the homology of the outer envelope protein B2L gene sequence of Orf virus, the source of infection to the Tellicherry goats was traced to the local goat. Although Orf virus is zoonotic; however, no occupational transmission was noticed in the present outbreak.