Lumpy skin disease virus, isolated in 2015 in Russia from cattle, is pathogenic for sheep at experimental infection

Lumpy skin disease is an economically significant transmissible infectious disease with mortatity rate from 4 to 95 %. Purebred animals are more susceptible to this infection, most seriously the disease occurs in young animals, not enough well-fed individuals, lactating cows. In Russia, the disease is registered since 2015. To eradicate this infection, it is necessary to study all components of the epizootic process. Currently, the studies on the pathogenicity of lumpy skin disease virus for sheep and goats and wild ruminants are insufficient to assess the role of such animals in the transmission of the virus. We estimated for the first time that lumpy skin disease virus isolated from cattle in the Republic of North Ossetia-Alania in 2015 is pathogenic for sheep. The causative agent was identified by sequencing the GPCR gene. In the experiment with 1.5-month-old lambs ( n = 4), intravenous and intradermal administration of the suspension of the biopsy samples from sick cows caused the formation of nodules on the skin at the sites of virus inoculation. Nodules were benign in nature, after two weeks it formed the scabs and separated from the skin. On the skin in places of formation nodules there were small scars. The genome of lumpy skin disease virus was detected by real-time PCR in blood samples collected from 9 to 17 days post infection, and in the oral swabs collected from 17 to 27 days post infection. The duration of viremia in lambs ranged from 3 to 8 days. The presence of infectious virus was confirmed by isolation of virus on continuous cell culture of sheep kidney. The clinical signs of the disease corresponded to 2 points calculated in accordance with clinical scoring system within the range from 0 («no visible response») to 10 points («severe generalization, requiring slaughter»). After euthanasia the samples of the liver, popliteal lymph node, lungs and spleen were collected to test for the presence of the viral genome. The genome of the virus was detected only in the lung and lymph nodes. So, our results confirmed literature data about pathogenicity of lumpy skin disease virus for sheep. Potentially, sheep can be involved in the epizootic process of lumpy skin disease as source of virus transmitted by blood feeding arthropods.