Isolation and Identification of Caprine Arthritis Encephalitis Virus from Animals in the Republic of Mordovia

SIMPLE SUMMARY: In the Russian Federation, small ruminant lentiviruses (SRLVs) circulate, causing slow infections that often develop and progress without clinical signs. The detection of seropositive animals leads to economic restrictions, including the prohibition of livestock product sales and the sale of breeding animals. In the investigation of biological samples from a clinically asymptomatic goat from a private farm, serological and molecular genetic methods (ELISA, PCR) yielded a positive result for lentivirus and antibodies against it. Subsequently, the virus was isolated in cell culture, and its presence was confirmed using transmission electron microscopy. Phylogenetic analysis revealed that the virus belongs to subtype B1. Extensive monitoring studies in different regions of the Russian Federation would give a clearer picture on the distribution of SLRVs and their classification. ABSTRACT: This article presents the results of virological and genetic studies of an isolate of caprine arthritis encephalitis (CAE) virus from the republic of Mordovia, Russian Federation. The isolate was found during monitoring studies of goat blood samples for the viral genome, and the presence of antibodies to lentiviruses was detected. According to the recommendation of the OIE, the positive result of PCR was confirmed with nucleotide sequencing. It was found that the obtained nucleotide sequence is identical to the genome of small ruminant lentiviruses presented in the GenBank database. Phylogenetic analysis showed that the isolate “Mordovia-2018” was included in the same cluster with an isolate from the Tver region of the Russian Federation detected in 2008. The sequence of the fragment of the env-gene of the isolate from the republic of Mordovia is available in GenBank under the number MN186380.1. To isolate the virus, a fraction of peripheral blood monocyte cells from the animal’s blood was added to a monolayer of lamb synovial membrane cell culture, and ten passages were carried out. The first manifestations of the cytopathic effect were observed after the third passage on the eighth day of cultivation in the form of single large cells of irregular shape with 5–7 nuclei. At the seventh passage, multiple syncytium with 7–12 nuclei were observed. At subsequent passage levels, the formation of syncytium containing more than 10–14 nuclei was observed.