Avian Flu Diary: China: MOA Reports HPAI H5N8 Outbreak In Wild Birds Yulin City, Shaanxi Province

#16,008

Three weeks ago, we looked at an HPAI H5N8 Outbreak In Wild Birds In Nagqu, Tibet, and overnight China's MOA has announced another wild-bird die-off due to HPAI H5N8, this time 1100 miles to the north and east at a nature preserve in Yulin City, Shaanxi province.

While these outbreaks may be much ado about nothing, in years past we've seen outbreaks of HPAI H5 in wild birds during the summer in China and Siberia as early signs that the virus may be mutating again.

A few (of many) examples.

In May of 2005 the first major expansion of H5N1 beyond Southeast Asia began when suddenly and unexpectedly, waterfowl (brown headed gulls, cormorants, ducks, geese, etc.) died en mass at Qinghai Lake, China- and quickly spread via migratory birds into Europe, Africa, and the Middle east signaling the emergence of clade 2.2 (aka QH05) of the H5N1 virus.

In 2009 researchers found evidence of another emerging clade - (2.3.2) - (see 2011 EID Journal New Avian Influenza Virus (H5N1) in Wild Birds, Qinghai, China), at Qinghai lake. In short order this emerging 2.3.2 clade began to show up in migratory birds, and poultry, from Japan to India, supplanting the old 2.2 clade in many regions.

In January of 2015 we saw another `Qinghai-like' die off of birds, this time in Henan Province, China which was subsequently identified as clade 2.3.2.1c (see Novel H5N1 Reassortment Detected In Migratory Birds - China). Within months this new sub clade was seen in Nigeria.

In June of 2016, in OIE: Russia - HPAI H5 In Wild & Migratory Birds, we saw a report of a number of birds taken by hunters earlier that month in and around Ubsu-Nur Lake in Russia that had tested positive for HPAI H5. Three months later it was confirmed by FAO/EMPRES to be H5N8 Clade 2.3.4.4., which by November of 2016 had sparked Europe's largest avian epizootic on record.

Over the summer of 2020, Russia reported die offs of wild birds, and outbreaks in poultry, due to HPAI H5N8. Last fall Europe began its second largest avian epizootic on record. Furthermore, Russia reported the 1st confirmed human infections with HPAI H5N8 the following December.

Now that HPAI H5N8 is considered to have some zoonotic potential (see CDC Adds Zoonotic Avian A/H5N8 To IRAT List), any changes in the virus take on new importance.

According to China's MOA, this is the 6th HPAI H5N8 wild bird die-off reported in China since the first of the year. First the (translated) statement, then I'll return with a postscript.

Wild bird H5N8 subtype highly pathogenic avian influenza outbreak occurred in Yulin City, Shaanxi Province

Release time: 2021-06-09
Source: Information Office of the Ministry of Agriculture and Rural Affairs

Ministry of Agriculture and Rural Information Office 6 Yue 9 release, the city of Yulin City, Shaanxi Province, Shenmu Hongjiannao National Nature Reserve occurs wildfowl H5N8 subtype highly pathogenic bird flu.

On June 9th , the Ministry of Agriculture and Rural Affairs received a report from the China Animal Disease Prevention and Control Center, and confirmed by the National Avian Influenza Reference Laboratory that a wild bird H5N8 subtype highly pathogenic avian influenza epidemic occurred in the Hongjiannao National Nature Reserve in Shenmu City . 4249 wild poultry died in the epidemic site . After the outbreak, the local area immediately activated an emergency response mechanism, carried out emergency response work, treated all sick and dead wild birds in a harmless manner, and disinfected the surrounding environment.

Since the beginning of this year, a total of 6 highly pathogenic avian influenza outbreaks (all wild birds) have been reported across the country . The outbreaks are in a spot state and no regional outbreaks have occurred.

Last month, in Science: Emerging H5N8 Avian Influenza Viruses, we looked at a review by two well-respected Chinese scientists (Weifeng Shi and George F. Gao) on the evolution, and growing zoonotic threat, of avian H5N8.

They don't address H5N8's jump to humans in Russia until every near the end (likely because data is still emerging on that incident), but the authors express deep concerns over this development, stating that:

the ". . . global spread of AIVs, particularly the H5N8 subtype, has become a major concern to poultry farming and wildlife security but, critically, also to global public health."
And due to the ". . . long-distance migration of wild birds, the innate capacity for reassortment of AIVs, the increased human-type receptor binding capability, and the constant antigenic variation of HPAIVs the authors warned that it was imperative that " . . . the global spread and potential risk of H5N8 AIVs to poultry farming, avian wildlife, and global public health are not ignored."