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BACKGROUND: Since 2005, highly pathogenic avian influenza A H5N1 viruses have spread from Asia worldwide, infecting poultry, humans and wild birds. Subsequently, global interest in avian influenza (AI) surveillance increased. OBJECTIVES: Mongolia presents an opportunity to study viruses in wild birds because the country has very low densities of domestic poultry and supports large concentrations of migratory water birds. METHODS: We conducted AI surveillance in Mongolia over two time periods, 2009-2013 and 2016-2018, utilizing environmental fecal sampling. Fresh fecal samples were collected from water bird congregation sites. Hemagglutinin (HA) and neuraminidase (NA) subtypes of positive samples were identified through viral isolation or molecular assays, with pathogenicity determined by HA subtype or sequencing the HA cleavage site. RESULTS: A total of 10,222 samples were collected. Of these, 7,025 fecal samples were collected from 2009 to 2013, and 3,197 fecal samples were collected from 2016 to 2018. Testing revealed 175 (1.7%) positive samples for low-pathogenicity influenza A, including 118 samples from 2009 to 2013 (1.7%) and 57 samples from 2016 to 2018 (1.8%). HA and NA subtyping of all positives identified 11 subtypes of HA and nine subtypes of NA in 29 different combinations. Within periods, viruses were detected more frequently during the fall season than in the early summer. CONCLUSION: Mongolias critical wild bird habitat is positioned as a crossroad of multiple migratory flyways. Our work demonstrates the feasibility of using an affordable environmental fecal sampling approach for AI surveillance and contributes to understanding the prevalence and ecology of low-pathogenicity avian influenza viruses in this important location, where birds from multiple flyways mix.

Background: Since 2005, highly pathogenic avian influenza A H5N1 viruses have spread from Asia worldwide, infecting poultry, humans and wild birds. Subsequently, global interest in avian influenza (AI) surveillance increased. Objectives: Mongolia presents an opportunity to study viruses in wild birds because the country has very low densities of domestic poultry and supports large concentrations of migratory water birds. Methods: We conducted AI surveillance in Mongolia over two time periods, 2009–2013 and 2016–2018, utilizing environmental fecal sampling. Fresh fecal samples were collected from water bird congregation sites. Hemagglutinin (HA) and neuraminidase (NA) subtypes of positive samples were identified through viral isolation or molecular assays, with pathogenicity determined by HA subtype or sequencing the HA cleavage site. Results: A total of 10,222 samples were collected. Of these, 7,025 fecal samples were collected from 2009 to 2013, and 3,197 fecal samples were collected from 2016 to 2018. Testing revealed 175 (1.7%) positive samples for low‐pathogenicity influenza A, including 118 samples from 2009 to 2013 (1.7%) and 57 samples from 2016 to 2018 (1.8%). HA and NA subtyping of all positives identified 11 subtypes of HA and nine subtypes of NA in 29 different combinations. Within periods, viruses were detected more frequently during the fall season than in the early summer. Conclusion: Mongolia's critical wild bird habitat is positioned as a crossroad of multiple migratory flyways. Our work demonstrates the feasibility of using an affordable environmental fecal sampling approach for AI surveillance and contributes to understanding the prevalence and ecology of low‐pathogenicity avian influenza viruses in this important location, where birds from multiple flyways mix. [ABSTRACT FROM AUTHOR]

African swine fever (ASF) is an infectious viral disease caused by African swine fever virus (ASFV), that causes high mortality in domestic swine and wild boar (Sus scrofa). Currently, outbreaks are mitigated through strict quarantine measures and the culling of affected herds, resulting in massive economic losses to the global pork industry. In 2019, an ASFV outbreak was reported in Mongolia, describing a rapidly progressing clinical disease and gross lesions consistent with the acute form of ASF; the virus was identified as a genotype II virus. Due to the limited information on clinical disease and viral dynamics within hosts available from field observations of the Mongolian isolates, we conducted the present study to further evaluate the progression of clinical disease, virulence, and pathology of an ASFV Mongolia/2019 field isolate (ASFV-MNG19), by experimental infection of domestic pigs. Intramuscular inoculation of domestic pigs with ASFV-MNG19 resulted in clinical signs and viremia at 3 days post challenge (DPC). Clinical disease rapidly progressed, resulting in the humane euthanasia of all pigs by 7 DPC. ASFV-MNG19 infected pigs had viremic titers of 108 TCID50/mL by 5 DPC and shed virus in oral secretions late in disease, as determined from oropharyngeal swabs. Whole-genome sequencing confirmed that the ASFV-MNG19 strain used in this study was a genotype II strain highly similar to other regional strains. In conclusion, we demonstrate that ASFV-MNG19 is a virulent genotype II ASFV strain that causes acute ASF in domestic swine. [ABSTRACT FROM AUTHOR]

In April 2020, two Whooper Swans (Cygnus cygnus) and one Swan Goose (Anser cygnoides) were found dead at three different locations in western Mongolia. Virus isolation from organs taken from the carcasses and full genome sequencing revealed that all three birds were positive for highly pathogenic H5N6 avian influenza virus (HPAIV) belonging to subclade 2.3.4.4h. Confirming similar reports from central Mongolia and western China, these findings have important implications for the monitoring, control, and management of HPAIVs in wild bird and commercial poultry populations in Mongolia. [ABSTRACT FROM AUTHOR]

African swine fever (ASF) is a severe haemorrhagic disease of domestic and wild pigs caused by the African swine fever virus (ASFV). In recent years, ASF has steadily spread towards new geographical areas, reaching Europe and Asia. On January 15th, 2019, Mongolia reported its first ASF outbreak to the World Organization for Animal Health (OIE), becoming, after China, the second country in the region affected by the disease. Following an event of unusual mortality in domestic pigs in Bulgan Province, a field team visited four farms and a meat market in the region to conduct an outbreak investigation and collect samples for laboratory analysis. Different organs were examined for ASF associated lesions, and total nucleic acid was extracted for real‐time PCR, virus isolation and molecular characterization. The real‐time PCR results confirmed ASFV DNA in 10 out of 10 samples and ASFV was isolated. Phylogenetic analysis established that ASFVs from Mongolia belong to genotype II and serogroup 8. The viruses were identical to each other, and to domestic pig isolates identified in China and Russia, based on the comparison of five genomic targets. Our results suggest a cross‐border spread of ASFV, without indicating the source of infection. [ABSTRACT FROM AUTHOR]