Lenina, Kyzyl, Tuva Republic, 667000 Russia, e-mail saryglar.1959@mail.ru Received October 4, 2016 A b s t r a c t Orf is infectious disease of sheep and goats, characterized by lesions of mucosa of the oral cavity, skin of lips, head, mammary glands and limbs. <...> The causal agent (virus of contagious ecthyma — Orf virus) is a member of genus Parapoxvirus, subfamily Chordopoxvirinae, family Poxviridae. <...> Genome of the Orf virus consists of linear double stranded DNA (138 kbp) and contains 132 open reading frames. <...> Its antigenic structure is poorly understood, and strains are not serologically identical. <...> We first identified Orf virus in sheep from Tuva Republic and studied biological properties of the isolate. <...> Disease of sheep, characterized by erythema, vesicles, pustules and scabs on ears and legs has been registered in August 2015 in Tuva Republic. <...> The scabs were sampled for isolation and identification of the causative agent. <...> For this result three lambs were experimentally infected with the scab suspension. <...> The mucocutaneous borders of the lips along the labial commissures were scarified and inoculum was loaded by cotton swabs. <...> The lip vesicles appeared at days 4-5 and then formed pustules and scabs. <...> The suspension of scabs from lips of infected lambs was used to inoculate sheep kidney cell culture. <...> In 7 days post inoculation the cell monolayer was harvested for second passage. <...> However, we did not observe specific cytopathic effect in the monolayers during these passages. <...> The skin swabs from experimentally infected lambs were examined by Real-Time PCR in accordance to the protocol developed by G. Venkatesan et al. (2014), and Orf virus DNA was detected at days 7 to 28 post infection. <...> The PCR test was positive for reference strain IA82 of Orf virus unlike other viruses (nodular dermatitis vaccine strain, sheep pox strains Mongolian and B5/96 or goatpox strain QA/A-04) that confirmed specificity of the PCR system. <...> Its analytical sensitivity to detect Orf virus genomic DNA was 1.3±0.03 lg TCD50/cm3. <...> Keywords: sheep, Orf virus, PCR, cell culture Orf is <...>