Molecular Characterization of Contagious Pustular Dermatitis Virus in goats of Sri Lanka

Abstract

Abstract Contagious Pustular Dermatitis (CPD), also known as Orf or Sore Mouth, is a zoonotic disease, in small ruminants. Contagious Pustular Dermatitis Virus (CPDV) is an epitheliotrophic DNA virus belongs to the Genus Parapoxvirus DNA virus Poxviridae family. CPD is characterized by papules and pustules typically found on and around muzzle, mouth and nose and eventually develop into thick scabs which become a site for secondary bacterial infections. CPD had been reported from all parts of Sri Lanka. In the North Central, Northern and Eastern provinces where 60% of national goat population is found, its incidence is higher. Laboratory confirmation and phylogenetic analysis of CPDV obtained through PCR and DNA sequencing respectively. Ninety two scab samples from affected animals were collected in 50% Glycerol phosphate saline from the following districts: Vavuniya, Trincomalee, Anuradhapura, Jaffna, Mannar, Kilinochchi and Kandy. Viral DNA was extracted and PCR was performed with modifications by using following primers ORF2F5’-CGAACTTCCACCTCAACCACTCC-3’ and ORF2R5’-CCTTGACGACGATGTCGCCCTTCT-3’. Partial B2L gene was amplified. B2L gene, which codes for an envelope protein, is highly conserved for CPDV. Hence, ten CPD positive samples (PCR products) representing different regions such as Trincomalee, Vavuniya, Anuradhapura, Kandy Kilinochchi and Jaffna were sequenced for partial B2L gene (507bp). Laboratory analysis showed that eighty-six samples were positive for CPD viral DNA. In phylogenetic analysis based on the partial B2L gene, the Sri Lankan strain was closer to the ORFV Assam/09 isolates (JN846834) from India. A12 strain (Anuradhapura) and ORFV Assam/09 isolates showed 99% similarity at the nucleotide levels. Two isolates from India (Accession No JN 846834, KU128538) were closely related to isolates from Anuradhapura, Mannar, Jaffna and Kilinochchi districts. Two isolates from China (Accession No KU 199831 and KC 568397) were closely related to isolates from Vavuniya and Trincomalee. Sri Lankan isolates are closely related with each other. Therefore one of the strains could be used as a vaccine candidate