Mass mortality in Caspian terns (Hydroprogne caspia), Pallas’s gulls (Ichthyaetus ichthyaetus), and Caspian gulls (Larus cachinnans) was recorded on the northeastern shores of the Caspian Sea in June 2022. More than 5000 gulls and terns died due to the outbreak. The outbreak was investigated in the field, and representative numbers of samples were collected and analyzed using pathological, virological, and molecular methods. Highly pathogenic avian influenza A (H5N1) viruses were detected and isolated from samples collected from dead birds. Genetic and phylogenetic analyses indicated that the hemagglutinin (HA) genes belonged to the clade 2.3.4.4.b of the H5Nx HPAI viruses, B2 sub-lineage, and were closely related to the highly pathogenic influenza viruses, caused an outbreak in wild birds with a high mortality rate in the western part of the Caspian Sea.

Bats are an important natural reservoir of various pathogenic microorganisms, and regular monitoring is necessary to track the situation of zoonotic infections. When examining samples from bats in South Kazakhstan, nucleotide sequences of putative novel bat adenovirus (AdV) species were found. Estimates of amino acid identities of the hexon protein have shown that potentially novel Bat mastadenovirus BatAdV-KZ01 shared higher similarity with monkey Rhesus adenovirus 59 (74.29%) than with Bat AdVs E and H (74.00%). Phylogenetically, BatAdV-KZ01 formed a separate clade, distant from Bat AdVs and other mammalian AdVs. Since adenoviruses are essential pathogens for many mammals, including humans and bats, this finding is of interest from both scientific and epidemiological points of view.

Low pathogenic H9N2 avian influenza viruses have become widespread in wild birds and poultry worldwide, raising concerns about their potential to spark pandemics or their role in enhancing the virulence and infectivity of H5Nx viruses through genetic reassortment. Therefore, influenza monitoring studies, including those of H9N2 viruses, are crucial for understanding, evaluating, and mitigating the risks associated with avian infections, and have broader implications for global public health. Although H9N2 viruses are not considered enzootic in Kazakhstan, they have been repeatedly detected in wild waterfowls and domestic poultry. In this study, all eight gene segments of influenza A/H9N2 viruses isolated in various regions of Kazakhstan between 2014 and 2020 were sequenced and analyzed. Molecular characterization revealed the presence of genetic markers associated with mammalian infectivity and disease potential. Furthermore, their predicted receptor binding site sequences indicate their potential capacity to attach to human-type receptors. These findings highlight the importance of continued surveillance and molecular investigation to better understand the evolution and zoonotic potential of H9N2 viruses in Kazakhstan.

After the recent Middle East Respiratory Syndrome coronavirus (MERS–CoV) pandemic in 2013, more attention has been paid to the camel as an important source of zoonotic viral infections. Almost simultaneously, in 2013, new genotypes 7 and 8 of the hepatitis E virus (HEV) were discovered in dromedary and Bactrian camels, respectively. HEV 7 was further shown to be associated with chronic viral hepatitis in a transplant recipient. In this study, serological screening for antibodies to MERS-CoV and hepatitis E virus was carried out on large camel farms in the south and west of Kazakhstan. 6.42% of the tested camels were found to be positive for antibodies to the hepatitis E virus, which indicates its circulation in local camel population. For the first time, antibodies to the hepatitis E virus were found in Bactrians, which have been little studied to date. Antibodies to MERS-CoV were not found in the camel sera.

Freshwater amphipods of the genus Gammarus are important trophic components of aquatic ecosystems and are increasingly considered a potential bioresource for aquaculture. However, their role in the maintenance and transmission of infectious agents remains poorly understood. This study evaluated the presence of major crustacean and fish pathogens in Gammarus lacustris populations from Kazakhstan and characterized associated viral communities using metagenomic sequencing. Six pooled samples collected from freshwater ecosystems across Kazakhstan were screened using PCR and RT-PCR assays targeting World Organisation for Animal Health (WOAH)-listed pathogens, including White Spot Syndrome Virus, Taura Syndrome Virus, Infectious Myonecrosis Virus, Aphanomyces astaci, and Aphanomyces invadans. In parallel, high-throughput sequencing (Illumina NovaSeq) was performed to assess virome composition and structure. No WOAH-listed pathogens were detected, suggesting a low detectable occurrence of major notifiable agents under the conditions of the present study. Metagenomic analysis revealed a virome dominated by RNA viruses, particularly picorna-like viruses (Picornaviridae), Dicistroviridae, and Marnaviridae. Phylogenetic and genome organization analyses identified potentially novel or highly divergent viral lineages within Picornavirales. Collectively, these findings suggest a favorable epizootiological profile of G. lacustris populations while highlighting freshwater amphipods as hosts of diverse and partially uncharacterized viral communities relevant to aquatic disease surveillance and aquaculture biosecurity.

Aislamiento y caracterización genética de un nuevo adenovirus asociado con la mortalidad masiva en cormoranes grandes (Phalacrocorax carbo). En 2021 se registró una alta mortalidad de cormoranes grandes (Phalacrocorax carbo) en el lago Alakol, en el este de Kazajstán, cuando murieron alrededor del 20% de las aves jóvenes. La secuenciación de alto rendimiento reveló la presencia de un supuesto nuevo adenovirus de cormorán significativamente divergente de los aviadenovirus conocidos. Sugerimos que este adenovirus de cormorán puede considerarse una amenaza emergente para la salud y conservación de esta especie.