Molecular evidence and phylogenetic analysis of orf virus isolates from outbreaks in Tripura state of North-East India
This study describes the first confirmed report of contagious ecthyma in Black Bengal goats from Tripura state, a North-Eastern state of India situated at the Indo-Bangladesh border. Outbreaks were characterized by the high rates of morbidity (58–67%), low mortality (8–10%) and case fatality (11–15%). The etiology of the outbreaks was confirmed as orf virus (ORFV) by standard virological/serological and molecular techniques including sequence analysis of B2L, a major envelop protein gene of genus Parapoxvirus. Sequence and phylogenetic analysis based on B2L gene of ORFV isolates from Tripura revealed that they were closely related to each other and also to other Indian isolates, in particular to ORFV-Shahjahanpur 82/04 isolate from North India. They revealed several specific nucleotide/amino acid substitutions, namely G299A (G100D), G660A, C705T, C795T (N267D) and G872A (R291H) which may be of notable epidemiological significance. This report necessitates the systematic investigation of orf outbreaks in susceptible populations including wild species particularly at transboundary regions by use of rapid diagnostics to control the infection by deploying an effective vaccine/therapeutics and better managemental practices.
KeywordsContagious ecthyma B2L Phylogeny Epidemiology Diagnostics Vaccines
The authors thank the Director, ICAR-Indian Veterinary Research Institute for providing necessary facilities to carry out this work and the staff of Pox virus laboratory, IVRI, Mukteswar, for their valuable and timely help in carrying out this work. The financial support provided by DBT, India under North-East Twinning program on DBT-NER on PPR-Pox project (BT/158/NE/TBP/2011) is also acknowledged.
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