High pathogenicity avian influenza (HPAI) has impacted poultry and wild birds globally. The number of H5 HPAI virus (HPAIV) infection cases in wild birds in Hokkaido (Northern Japan) was high in the last two seasons, contributing to virus spillover to resident birds and poultry. Therefore, H5 HPAIVs in birds and mammals in Hokkaido in winter 2022–2023 and 2023–2024 were monitored and viruses were phylogenetically, antigenically, and pathogenetically characterized. Thirty HPAIV isolates were subtyped and pathotyped by sequencing the hemagglutinin (HA) gene of viruses. Phylogenetic analysis of the HA gene revealed that all isolated HPAIVs were categorized into clade 2.3.4.4b and divided into three groups (G2b, G2c, and G2d). Most isolates belonging to subgroup G2d clustered with isolates in winter 2021–2022 in Hokkaido. The other isolates were categorized into two subgroups, G2b and G2c, mainly composed of isolates in Honshu Island in winter 2021–2022 and 2022–2023, respectively. Two H5 HPAIVs isolated in Eastern Russia in spring and autumn 2022 were genetically close to most Hokkaido isolates (G2d), and a virus isolated in Hokkaido in November 2023 was also grouped in subgroup G2d. Further analysis of all eight gene segments identified six types of gene constellations. Cross‐hemagglutination inhibition test indicated that the antigenicity of H5 HPAIVs isolated in the last several seasons was similar within them but slightly different from that in the 2010s. Three chicken breeds were intranasally challenged with four representative isolates to assess their pathogenicity. All chickens except one broiler chicken were dead until 5‐day postchallenge with different pathogenicity of these viruses. The pathogenicity of one HPAIV strain was significantly lower in broiler chickens than in layer chickens. The mixture of multiple characteristics of HPAIVs in Hokkaido was confirmed by bird migration routes. Thus, many HPAIVs can be brought and scattered anywhere on Earth.

In 2021, several isolates of the H5N5 avian influenza virus (AIV) were detected in Europe and the Russian Federation, which differed from those detected in 2020. Genetic analysis revealed a relationship between the highly pathogenic avian influenza H5N5 subtype, detected in Europe, and some isolates detected in the Russian Federation territory in 2020–2021: it was shown that both originated in the Caspian Sea regions around the autumn of 2020. The appearance of H5N5 subtype viruses in the spring of 2021 in Europe and the Russian Federation was not associated with the mass migration of birds from Africa. The results of the analysis revealed the presence of a deletion in the stem of a neuraminidase between bp 139 and 204 (open reading frame). It has been shown that AIVs of the H5N5 subtype are capable of long-term circulation in wild bird populations with the possibility of reassortment. The results also highlighted the need for careful monitoring of the circulation of AIVs in the Caspian Sea region, the role of which, in the preservation and emergence of new antigenic variants of such viruses in Eurasia, is currently underestimated.

Newcastle disease virus (NDV, Avian orthoavulavirus type 1, AOAV-1) is a contagious high-impact poultry pathogen with infections detected worldwide. In the present study, 19,500 clinical samples from wild bird species and poultry collected from 28 regions of Russia between 2017 and 2021 were screened for the presence of the AOAV-1 genome. NDV RNA was detected in 15 samples from wild birds and 63 samples from poultry. All isolates were screened for a partial sequence of the fusion (F) gene that included the cleavage site. Phylogenetic analysis demonstrated that lentogenic AOAV-1 I.1.1, I.1.2.1, and II genotypes were dominant among vaccine-like viruses in the territory of the Russian Federation. A vaccine-like virus with a mutated cleavage site (112-RKQGR^L-117) was detected in turkeys. Among the virulent AOAV-1 strains, viruses of the XXI.1.1, VII.1.1, and VII.2 genotypes were identified. The cleavage site of viruses of the XXI.1.1 genotype had a 112-KRQKR^F-117 amino acid sequence. The cleavage site of viruses with VII.1.1 and VII.2 genotypes had a 112-RRQKR^F-117 amino acid sequence. The data collected by the present study demonstrate the distribution and dominance of the virulent VII.1.1 genotype in the Russian Federation between 2017 and 2021.

Introduction. African swine fever virus (ASFV) is a large, double-stranded DNA virus in the Asfarviridae family. It is the causative agent of African swine fever (ASF). Only the genome of BA71V strain, adapted to Vero cell culture, was fully analyzed.The aim of this study was analyzing the complete genome sequence of two strains of adapted to the growth in CV-1 cell culture (CC) ASFV obtained after 30 and 50 passages, in comparison to the parental virus.Material and methods. ASFV isolate Odintsovo 02/14 (parental), ASFV adapted variants ASFV/ARRIAH/CV-1/30 and ASFV/ARRIAH/CV-1/50 were all used to extract genomic DNA (gDNA). Sequencing library was constructed using the «Nextera XT DNA library preparation kit» («Illumina», USA).Results. Genomes of ASFV/ARRIAH/CV-1/30 and ASFV/ARRIAH/CV-1/50 consisted of 186 529 bp and 186 525 bp, respectively. Total 78 single nucleotide polymorphisms (SNPs) were identified between the parental Odintsovo 02/14 and the two high passaged strains, as well as a 2947 bp large-size deletion in the 3’ variable region of adapted viruses was detected.Discussion. ASFV as a DNA-containing virus may not have a very high level of mutation, but this is the second study showing that adaptation to growth in continuous CC leads to large deletions in the genome of the virus.Conclusion. Mutations in the protein-coding regions of the genome can be synonymous and non-synonymous, i.e. leading to amino acid substitution. Additional research is needed to understand the influence of the mutations described in the adaptation process on the reproduction of the virus and its virulence.

Проведено описательное ретроспективное эпизоотологическое исследование в Амурской области (Дальний Восток России), где в 2018 г. выявлена вспышка бешенства, целью которого было проанализировать возможные пути заноса и особенности пространственно-временного распространения бешенства на территорию, которая оставалась свободной от этой инфекции с 1972 до 2018 г. В 2018-2021 гг. на бешенство были исследованы пробы головного мозга, полученные от 1416 животных. Подтверждено 47 случаев бешенства, доля диких животных (Vulpes vulpes, Nyctereutes procyonoides, Canis lupus) составила 66%. Первые случаи выявлены на расстоянии до 30 км от государственной границы с Китаем. Определены нуклеотидные последовательности гена нуклеопротеина 3 изолятов вируса бешенства и установлена их принадлежность к генетической линии Arctic-like-2. Генетически наиболее близкие к ним изоляты вируса бешенства были выявлены в провинции Хэйлунцзян (Китай, 2011 и 2018 гг.) и Еврейской автономной области (Россия, 1980 г.). Для картографирования случаев бешенства использовали геоинформационные системы и открытые данные дистанционного зондирования Земли. После 2018 г. эпизоотия распространялась в пределах лесостепных ландшафтов Зейско-Буреинской равнины, где заболевания людей и животных регистрировалось в прошлом (до 1972 г.). Фронт эпизоотии распространялся в северо-восточном направлении со средней скоростью 59 (16-302) км за один эпизоотический год (цикл). Занос вируса бешенства наиболее вероятен по долине реки Амур из неблагополучных по бешенству районов России и Китая, расположенных ниже по...

Rabies is a fatal disease of mammals that poses a high zoonotic risk to humans as well. The distribution of rabies is mainly driven by host animal migration and human-mediated dispersion. To contribute to the global understanding of the rabies virus (RABV) molecular epidemiology, 94 RABV field isolates collected from animals in 13 European Russian regions were phylogenetically characterized using the nearly full-size N gene nucleotide sequences. According to phylogenetic inferences, all isolates belonged to one of the two established phylogenetic groups, either group C (n = 54) or group D (n = 40), which are part of the clade Cosmopolitan of RABVs. Some representatives of group C collected from regions located far apart from each other had a remarkably high level of nucleotide identity. The possibility of the contribution of local bat species to the distribution of RABVs was discussed. Interestingly, over the years, the fraction of group D isolates has been constantly decreasing compared with that of group C isolates. The phylogenetic insights generated herein might have an important contribution to the control and surveillance of animal rabies epidemiology in the region.