Equine piroplasmosis (EP) is a global worldwide infection, which can lead to the death of animals. Despite the causative agents of EP being well studied, there are no data on the distribution and genetic characteristics of EP agents in any region of Russia. In this study, blood samples from 750 horses from Novosibirsk province, Irkutsk province, and Altai region of Russian Siberia were examined for the presence of EP agents. Theileria equi and Babesia caballi were detected in all examined regions, with mean prevalence rates of 60.4

Background: A descriptive epidemiological study of the rabies outbreak in the Amur Region of Russia (ARR), which remained rabies-free from 1972 to 2017, was carried out. During 2018-2022, 49 animal rabies cases and one human rabies death were documented in the ARR. This study aimed to detect possible ways of incursion and features of the spatial spread of rabies virus (RABV) in ARR, which was considered rabies-free for 45 years. Methods: After the beginning of the outbreak, 1,450 animal brain samples were tested using a direct fluorescent antibody test. Genetic analysis of RABV isolates was carried out (n = 9). GIS was used to analyze the spatial spread of rabies in ARR and adjacent territories. Results: Rabies has been confirmed in red foxes (Vulpes vulpes ) - 38.8%, raccoon dogs (Nyctereutes procyonoides ) - 10.2%, wolves (Canis lupus ) - 14.3%, dogs - 18.4% and farm animals - 18.3% (n = 49). The first cases were detected south of the ARR, 30 km from the state border between Russia and China. In 2018-2022, the RABV spread within the forest-steppe landscapes of the Zeya-Bureya Plain northwesterly; the maximum distance from the first recorded event was 192.4 km (Me = 77.6). According to a phylogenetic analysis, the isolates from ARR belonged to the Acrtic-like-2 RABV lineage and showed the maximum similarity to the isolates recovered in the province of Heilongjiang (China, 2011, 2018) and the Jewish Autonomous Region (Russia, 1980). Conclusion: Rabies was most likely introduced by wild carnivores from the adjacent territories of Russia or China, located downstream of the Amur River.

Background. Cattle anaplasmosis and babesiosis and theileriosis of horses are a group of natural focal vector-borne diseases that cause significant economic damage to livestock and horse breeding around the world. On the territory of the Baikal region these diseases and their pathogens remain little explored. Purpose – to study the epizootic situation of blood-parasitic diseases of farm animals in the Irkutsk region, to establish the species affiliation of the identified pathogens and their genetic diversity. Materials and methods. For the presence of Babesia spp./Theileria spp. and Anaplasma spp. has been researched659 horse blood samples, 579 sheep blood samples, 25 goat blood samples and 647 cattle blood samples. For the detection of babesia and theileria, nested two-round PCR with primers from the 18S rRNA gene region was used, and for the detection of anaplasma DNA with primers from the 16S rRNA gene region. For study the genetic diversity of the identified pathogens, selective sequencing of samples was carried out with subsequent phylogenetic analysis. Results. The DNA of Anaplasma spp. was detected in blood samples of small ruminants from 12 districts of the region. The infection rate of sheep and goats was 68.7±1.9% and 68%±9.3%, respectively. Nucleotide sequences of the 16S rRNA gene fragment were determined in 68 A. ovis samples from the blood of sheep and goats. The researched sequences were conservative for the studied gene and differed from each other in two heterozygous sites of the gene(T/C and G/A nucleotide substitutions).They corresponded to the sequences of the prototype strain Haibei (CP015994), as well as to the A. ovis sequences previously found in the blood of sheep from Altai (Russia) and Mongolia, deer and D. niveus and D. nuttalli ticks from China. DNA of Babesia spp./Theileria spp. found in blood samples of horses from 13 districts of the region. The average infection of horses was 64.2%±1.9%. Two etiological agents of equine piroplasmosis were found in the blood of the examined horses: T. equi (genetic groups A and E) and B. caballi. Definite sequences of the B. caballi 18S rRNA gene (700–1146 bp) were identical to each other and differed by at least ten substitutions and one deletion from the sequences available in the GenBank database. However, the greatest similarity was observed with B. caballi sequences found in the blood of a horse from Brazil (KY952238), ticks from Kazakhstan (MN907451) and China (MN173021). The results indicate that DNA of Anaplasma and Babesia in the blood of cattle have not been identified. Conclusion: The data received evidence a wide distribution of foci of small cattle anaplasmosis and piroplasmosis of horses in the Irkutsk region and the need to continue monitoring their epizootic condition.

INTRODUCTION:Malignant catarrhal fever (MCF) is a rare, under-explored lethal viral infection of cattle with gammaherpesvirus aetiological agents. Most often, the disease occurs on farms where cattle and sheep are kept together. However, other trigger mechanisms and environmental factors contribute. This study investigates the causation of MCF.MATERIAL AND METHODS:An outbreak of MCF occurred in June - August 2017 in Kharchev village in Irkutsk Oblast, Russia. In this paper, we provide epidemiological (sanitary status of pastures, watering places, and premises) and weather data during the outbreak, and descriptions of the clinical signs and post-mortem changes in cattle. The virus was detected and isolated from pathological material samples and identified by molecular methods.RESULTS:Extreme weather conditions, mixed-herd cattle and sheep farming, and unsatisfactory feed quality contributed to the outbreak. A virus related to herpesvirus OvHV2 was isolated and typed (MCF/Irkutsk/2017). Phylogenetic analysis showed its close genetic relationship to isolates from cattle and sheep in Germany, USA, and the Netherlands.CONCLUSION:Sporadic outbreaks of MCF caused by biotic and abiotic factors together are typical for the Russian Federation, and the Irkutsk outbreak epitomised this. Temperature anomalies caused pasture depletion, resulting in feed and water deficiency for grazing animals and dehydration and acidosis. Heat stress in animals ultimately led to the occurrence of MCF in the herd.

The Baikal seal is the only endemic mammal of Lake Baikal. In late October 2017, 132 dead Baikal seals were found on the shore of the lake. To identify causes of death, postmortem necropsy, virological, chemical toxicological, microbiological, and parasitological studies were carried out. Several hypotheses for explaining the causes of the deaths were put forward. The most probable causes are heart failure and asphyxia due to echo sounders (sonar). The causes were confirmed by the results of histological examination of the hearts and lungs of a large number of dead seals found on the southern shore of Lake Baikal (a center for the fishing industry).

Equine piroplasmosis is a natural tick-borne infection caused by hemoprotozoan parasites of the order Piroplasmida, Babesia caballi and Theileria equi. Animals that recover from piroplasmosis remain persistently infected carriers and can transmit pathogens to vector ticks. Cases of equine piroplasmosis are periodically observed in Siberia, however, no agent of equine piroplasmosis has yet been genetically characterized in Russia. The aim of this work was studying the prevalence of the infectious agents of piroplasmosis in horses from Siberia and genotyping the detected agents. Blood samples from 155 horses were examined for the presence of Babesia and Theileria DNA by nested PCR with the subsequent sequencing of positive samples. DNA of T. equi was found in blood samples from 57.9 %, 38.5 % and 65.0 % of horses from Novosibirsk province, Irkutsk province, and the Republic of Altai, respectively. T. equi DNA was found in the samples from almost all sampling sites included in this study, indicating that most of the studied sites are endemic for equine theileriosis. Surprisingly, DNA of B. caballi was not found in any of the samples examined, even though this agent had previously been detected in many regions in Russia, including Altai. The analysis of the determined 18S rRNA gene sequences demonstrated that T. equi samples belonged to two genetic groups, which differed significantly by the sequences of the variable (V4) region of the gene. All T. equi sequences from group B were identical and corresponded to T. equi sequences found in the blood of horses from China and Korea, while T. equi sequences from group A differed by 1–5 nucleotide substitutions and were identical to the sequences from the blood of horses from India and Brazil or differed from them by single mismatches. Notably, in this study the presence of etiological agent of piroplasmosis in blood samples from horses in Russia was genetically confirmed for the first time.