Commonground
Senior Moderator
Volume 30, Number 10—October 2024
Dispatch
Highly Pathogenic Avian Influenza A Virus in Wild Migratory Birds, Qinghai Lake, China, 2022
Abstract
In July 2022, an outbreak of highly pathogenic avian influenza A(H5N1) virus clade 2.3.4.4b occurred among migratory birds at Qinghai Lake in China. The virus circulated in June, and reassortants emerged after its introduction into the area. Surveillance in 2023 showed that the virus did not establish a stable presence in wild waterfowl.
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Conclusions
Our surveillance data showed H5N1 clade 2.3.4.4b virus emerged in summer 2022 in the Qinghai Lake area. Because there is no poultry in the vicinity of Qinghai Lake, the virus was likely spread because of migratory birds, similar to the case for H5N8 in 2016 (6). In 2023, the H5N1 clade 2.3.4.4b virus was not detected, suggesting that this virus does not exhibit sustained circulation among wild birds at Qinghai Lake. Because the H5N1 clade 2.3.4.4b virus continues to circulate in other regions (14), it is possible for reintroduction to Qinghai Lake to cause an outbreak. Therefore, continuous surveillance of avian influenza virus in wild birds at Qinghai Lake is necessary.
The H5N1 clade 2.3.4.4b viruses isolated in this study had amino acid mutations associated with increased virulence and replication in mammals. Our animal experiment also demonstrated that genotype G1 of the H5N1 strain resulted in death in mice, suggesting that the virus has the potential to spill over to nonhuman mammals. Many livestock (mainly sheep, goats, and yaks) graze around Qinghai Lake, and wild birds and livestock often graze on the same grassland. A risk for transmission of H5N1 clade 2.3.4.4b virus from infected birds to livestock at Qinghai Lake exists, similar to bird-to-cow transmission of H5N1 clade 2.3.4.4b previously reported in the United States (15). Avian influenza virus surveillance should include livestock around Qinghai Lake.
https://wwwnc.cdc.gov/eid/article/30/10/24-0460_article
Dispatch
Highly Pathogenic Avian Influenza A Virus in Wild Migratory Birds, Qinghai Lake, China, 2022
Abstract
In July 2022, an outbreak of highly pathogenic avian influenza A(H5N1) virus clade 2.3.4.4b occurred among migratory birds at Qinghai Lake in China. The virus circulated in June, and reassortants emerged after its introduction into the area. Surveillance in 2023 showed that the virus did not establish a stable presence in wild waterfowl.
-snip-
Conclusions
Our surveillance data showed H5N1 clade 2.3.4.4b virus emerged in summer 2022 in the Qinghai Lake area. Because there is no poultry in the vicinity of Qinghai Lake, the virus was likely spread because of migratory birds, similar to the case for H5N8 in 2016 (6). In 2023, the H5N1 clade 2.3.4.4b virus was not detected, suggesting that this virus does not exhibit sustained circulation among wild birds at Qinghai Lake. Because the H5N1 clade 2.3.4.4b virus continues to circulate in other regions (14), it is possible for reintroduction to Qinghai Lake to cause an outbreak. Therefore, continuous surveillance of avian influenza virus in wild birds at Qinghai Lake is necessary.
The H5N1 clade 2.3.4.4b viruses isolated in this study had amino acid mutations associated with increased virulence and replication in mammals. Our animal experiment also demonstrated that genotype G1 of the H5N1 strain resulted in death in mice, suggesting that the virus has the potential to spill over to nonhuman mammals. Many livestock (mainly sheep, goats, and yaks) graze around Qinghai Lake, and wild birds and livestock often graze on the same grassland. A risk for transmission of H5N1 clade 2.3.4.4b virus from infected birds to livestock at Qinghai Lake exists, similar to bird-to-cow transmission of H5N1 clade 2.3.4.4b previously reported in the United States (15). Avian influenza virus surveillance should include livestock around Qinghai Lake.
https://wwwnc.cdc.gov/eid/article/30/10/24-0460_article