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

Abstract

Contagious Pustular Dermatitis (CPD), is a zoonotic disease of small ruminants causing severe deterioration of skin. Contagious Pustular Dermatitis Virus (CPDV) is an epitheliotrophic virus belonging to the parapox virus. Accurate information on CPD in Sri Lanka is scarce. This study was conducted to investigate the prevalence and to characterize the CPD virus from goats in Sri Lanka and select a suitable CPDV strain as a vaccine candidate since no vaccines are available in Sri Lanka. Laboratory confirmation and phylogenetic analysis of CPDV were obtained through PCR and DNA sequencing respectively. Ninety-two scab samples from infected animals were collected in 50% Glycerol phosphate saline from the following districts of Sri Lanka: Vavuniya, Trincomalee, Anuradhapura, Jaffna, Mannar, Kilinochchi and Kandy. Viral DNA was extracted and PCR was performed with modifications by using the following primers ORF2F5’-CGAACTTCCACCTCAACCACTCC-3’ and ORF2R5'-CCTTGACGACGATGTCGCCCTTCT-3'. The partial B2L gene was amplified. The B2L gene, which codes for an envelope protein, is highly conserved for CPDV. Laboratory analysis showed that eighty-six samples were positive for CPD viral DNA. In the 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. Sri Lankan isolates are closely related to each other. Therefore, one of the strains could be used as a vaccine candidate. Two isolates from India (Accession No JN 846834, KU128538) were closely related to isolates from the 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.