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J Vet Sci
. 2026 Jul;27(4):e38.
doi: 10.4142/jvs.25274.
Clade 2.3.4.4b H5N1 highly pathogenic avian influenza detected in wild bird feces, Eastern Mongolia, 2024
Se-Hee An # 1 , Temuulen Myagmarsuren # 2 , Gyeong-Beom Heo 1 , Hwanseok Jeong 1 , Yong-Myung Kang 3 , Urankhaich Dondog 2 , Unurjavkhlan Tsogbadrakh 2 , Youn-Jeong Lee 1 , Erdene-Ochir Tseren-Ochir 4 , Kwang-Nyeong Lee 5
Affiliations
Importance: Despite ongoing intercontinental spread of clade 2.3.4.4b H5N1 highly pathogenic avian influenza (HPAI), surveillance data from Mongolia -- a critical junction between Central and East Asian migratory flyways -- remain scarce, leaving a gap in understanding how viruses move between northern breeding areas and southern wintering grounds.
Objective: We aimed to detect and genetically characterize HPAI viruses in wild bird populations in Mongolia and assess their relationship with viruses circulating in East Asia.
Methods: Active surveillance was conducted at Ganga Lake, Mongolia, in October 2024. A total of 352 wild bird fecal samples were collected and tested for AIVs. Viral isolates were subtyped, whole-genome sequenced, and phylogenetically analyzed. Host species was identified using c oxidase I barcoding.
Results: Sixteen AIVs were isolated, including one clade 2.3.4.4b H5N1 HPAI virus (M9-3) from whooper swan feces. Genomic analysis revealed M9-3 had > 99% similarity with Korean and Japanese H5N1 isolates reported in late 2024 and undergone recent reassortment and disseminated through migratory flyways.
Conclusions and relevance: This is the first detection of clade 2.3.4.4b H5N1 in Eastern Mongolia in a fecal sample during late autumn. These findings underscore Mongolia's importance as a sentinel location for interregional HPAI dissemination.
Keywords: Interregional dissemination; breeding and wintering grounds; one health; phylogenomics; whooper swan.
. 2026 Jul;27(4):e38.
doi: 10.4142/jvs.25274.
Clade 2.3.4.4b H5N1 highly pathogenic avian influenza detected in wild bird feces, Eastern Mongolia, 2024
Se-Hee An # 1 , Temuulen Myagmarsuren # 2 , Gyeong-Beom Heo 1 , Hwanseok Jeong 1 , Yong-Myung Kang 3 , Urankhaich Dondog 2 , Unurjavkhlan Tsogbadrakh 2 , Youn-Jeong Lee 1 , Erdene-Ochir Tseren-Ochir 4 , Kwang-Nyeong Lee 5
Affiliations
- PMID: 42551976
- DOI: 10.4142/jvs.25274
Importance: Despite ongoing intercontinental spread of clade 2.3.4.4b H5N1 highly pathogenic avian influenza (HPAI), surveillance data from Mongolia -- a critical junction between Central and East Asian migratory flyways -- remain scarce, leaving a gap in understanding how viruses move between northern breeding areas and southern wintering grounds.
Objective: We aimed to detect and genetically characterize HPAI viruses in wild bird populations in Mongolia and assess their relationship with viruses circulating in East Asia.
Methods: Active surveillance was conducted at Ganga Lake, Mongolia, in October 2024. A total of 352 wild bird fecal samples were collected and tested for AIVs. Viral isolates were subtyped, whole-genome sequenced, and phylogenetically analyzed. Host species was identified using c oxidase I barcoding.
Results: Sixteen AIVs were isolated, including one clade 2.3.4.4b H5N1 HPAI virus (M9-3) from whooper swan feces. Genomic analysis revealed M9-3 had > 99% similarity with Korean and Japanese H5N1 isolates reported in late 2024 and undergone recent reassortment and disseminated through migratory flyways.
Conclusions and relevance: This is the first detection of clade 2.3.4.4b H5N1 in Eastern Mongolia in a fecal sample during late autumn. These findings underscore Mongolia's importance as a sentinel location for interregional HPAI dissemination.
Keywords: Interregional dissemination; breeding and wintering grounds; one health; phylogenomics; whooper swan.