| Summary The  authors describe the isolation and identification of orf virus (ORFV) from an  outbreak in a flock of sheep at Mukteswar, Uttarakhand, India, in 2009. The  causative agent, ORFV was successfully isolated in primary lamb testes cells  and identified using a semi-nested diagnostic polymerase chain reaction (PCR)  and sequence and phylogenetic analyses of immunogenic envelope protein (B2L) coding gene. The  affected animals showed characteristic proliferative skin lesions around the  mouth and on nostrils and, in a few animals, lesions were also noticed on the  tongue irrespective of age and sex. The morbidity, mortality and case fatality  rates observed were 6%, 45% and 13%, respectively. Clinical samples were  initially screened by counter immuno-electrophoresis and the serum  neutralisation test; further positive skin scabs were tested with diagnostic  PCR and virus isolation was performed on primary or secondary lamb testes  cultures. Sequencing and phylogenetic analyses of the sheep isolate based on  the B2L gene  revealed that the isolate was closest to a goat isolate retrieved from an  outbreak at the same geographic location in 2000. Furthermore, it also showed  close genetic similarities with other Indian isolates reported earlier. Regular  and systematic investigation of outbreaks is necessary to monitor the disease  in susceptible populations. The development of rapid diagnostic methods as well  as effective vaccine to control this infection not only from India but also  other parts of the world is called for.
 KeywordsContagious  ecthyma, Epidemiology, India, Orf, Parapoxvirus, Phylogenetic analysis,  Polymerase chain reaction, Sequence, Virus.
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