Introduction. In July 2021, a mass mortality of seabirds of unclear etiology occurred on the coast of the Sea of Japan in the Khasansky district of Primorsky Krai. According to the Department for Protection of Wildlife and Specially Protected Natural Territories of Primorsky Krai, over a thousand dead birds were found on the coast. The main case occurred in the population of birds Rhinoceros auklets (Cerorhinca monocerata, Alcidae), also among the dead birds were found several dozens of gulls (Larus spp.) and terns (Sterna spp.), single individuals of other species. The peak of mortality in bird populations occurred on July 13–17, 2021. This territory is a recreational area, in the summer months a large number of people rest there. The current situation has caused increased attention of the entire scientific community, as well as organizations that protect the citizens health and the environment. The aim. To establish possible etiology of the epizootic outbreak and describe the cause of birds’ death.Materials and methods. Comprehensive examination using classical methods of virology, microbiology and toxicology, as well as the most modern research methods such as MALDI TOF-mass spectrometry and NGS.Conclusion. As a result of the studies, it was determined that the cause of birds’ death was infectious peritonitis with endogenous intoxication syndrome induced by a complex of pathogenic microorganisms, such as enteropathogenic Escherichia coli, Proteus vulgaris, Proteus mirabilis, Proteus pennery, Enterococcus faecalis and Wickerhamomyces anomalus, related to Candida pelliculosa.

Aim. The aim of this work was to briefly summarize the current understanding of the phenomenon of echolocation in the order of bats (Chiroptera Blumenbach, 1779).Discussion. The paper discusses: the place of bats among other taxonomic groups of animals that have the ability of echolocation; the history of the discovery of "ear vision" in bats by L. Spallanzani in the 18th century; the first scientifically based assumptions regarding the use of ultrasound by bats and the discovery of this phenomenon in the middle of the last century; methods for emitting and receiving ultrasound by various taxonomic groups of bats; physical patterns underlying the propagation of ultrasonic waves; characteristics of the returned echo and algorithms for echolocation in bats; echolocation interactions between insectivorous bats and nocturnal moths and possibilities for ultrasonic monitoring of bat populations.Conclusion. The inclusion of ultrasound monitoring of bat populations in integrated ecological and virological studies could form a new point of growth in systems to ensure biological security at both national and global levels.

Aim. Aim of this the research presented in this article is to analyze the representation of bat (Chiroptera) viruses in various taxa of the Virae kingdom.Discussion. Currently, 260 viruses are associated with bats belonging to 19 orders, 28 families (9 DNA‐containing and 19 RNA‐containing) and 61 genera (18 DNA‐containing and 43 RNA‐containing). This number includes viruses annotated by the International Committee on the Taxonomy of Viruses (excluding synonymous species) for which the taxonomic status has been verified by sequencing subgenomic or full‐genomic nucleotide sequences. A large number of unidentified strains from bats are noteworthy – they apparently contain many future prototype viruses for new taxa.Conclusion. The data presented in this article will undoubtedly be expanded in the nearest future. This is due to the need to improve the system for prevention of dangerous epidemic and pandemic situations primarily by increasing priority attention on bat viruses. Therefore, the catalogue of bat viruses, known as of mid‐2020, presented in this paper could be considered as a kind of "starting point" for future research in this area.