African swine fever (ASF) is an emerging disease threat for the swine industry worldwide. No ASF vaccine is available and progress is hindered by lack of knowledge concerning the extent of ASF virus (ASFV) strain diversity and the viral antigens responsible for protection in the pig. Available data from vaccination/challenge experiments in pigs indicate ASF protective immunity is haemadsorption inhibition (HAI) serotype-specific. A better understanding of ASFV HAI serological groups and their diversity in nature, as well as improved methods to serotype ASFV isolates, is needed. Here, we demonstrated that the genetic locus encoding ASFV CD2v and Ctype lectin proteins mediates HAI serological specificity and that CD2v/C-type lectin genotyping provides a simple method to group ASFVs by serotype, thus facilitating study of ASFV strain diversity in nature, and providing information necessary for eventual vaccine design, development and efficacious use.

The first notifications of the unknown disease of cattle appeared in September-October 2015 in North Caucasus region of Russia (Republic of North Ossetia-Alania). The clinical signs included watery discharge from eyes, apathy, loss of appetite, salivation, lameness and nodular skin lesions. Capripoxvirus genome was detected by real-time PCR in the tissue samples of sick animals. The aetiological agent was isolated in the primary cell cultures of lamb testis and goat testis, as well as in the continuous MDBK cell culture. Further sequencing of the GPCR gene and phylogenetic analysis showed the close genetic relationship of isolated capripoxvirus with a group of lumpy skin disease virus. Koch's postulates were fulfilled by the experimental infection of four calves with a suspension of tissue samples from sick animals.

A b s t r a c tLumpy 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 confirm 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.

A b s t r a c tOrf 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 ecthymaOrf 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. That is why the investigation of novel isolates of Orf virus is actual. However, we are not aware of such research in Russia possibly due to rare outbreaks recognized. 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. After 2 weeks the lesions healing occurred. 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. We also detected Orf virus DNA in scabs from the infected lambs and in lysates of the monolayers harvested after second passage. 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 TCD 50 /cm 3 . Thus, the pathogen which caused the disease of sheep in Tuva Republic in 2015 was isolated from experimentally infected lambs using sheep kidney cell culture and identified as Orf virus.

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