Credit Wikipedia
#15,972
While today's announcement from China's MOA may signify little, obscure reports of die offs of wild birds from avian flu - often in late spring or early summer, and occurring in western China or central or eastern Siberia - have a history of coming back to bite us the following fall.
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.
Wild bird H5N8 subtype highly pathogenic avian influenza outbreak in Nagqu, Tibet
Release time: 2021-05-19
Source: Information Office of the Ministry of Agriculture and Rural Affairs
The Information Office of the Ministry of Agriculture and Rural Affairs announced on May 19 that a wild bird H5N8 subtype highly pathogenic avian influenza epidemic occurred in Nagqu City, Tibet Autonomous Region.
On May 19, the Ministry of Agriculture and Rural Affairs received a report from the China Animal Disease Prevention and Control Center, which was confirmed by the National Avian Influenza Reference Laboratory. Type highly pathogenic avian influenza epidemic. There were 268 wild fowls that 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.
Once considered controversial, today there is little doubt that HPAI viruses are spread over long distances by migratory birds (see WHO: Migratory Birds & The Potential Spread Of Avian Influenza).
The major migratory bird flyways (shown below) - along with scores of minor pathways (not depicted) - serve as a global interstate highway for avian influenza viruses. While primarily north-south conduits, there is enough overlap to allow for east-west movement as well.
A study, published in 2016 (see Sci Repts.: Southward Autumn Migration Of Waterfowl Facilitates Transmission Of HPAI H5N1), suggests that waterfowl pick up new HPAI viruses in the spring (likely from poultry or terrestrial birds) on their northbound trip to their summer breeding spots - where they spread and potentially evolve - and then redistribute them on their southbound journey the following fall.
A cycle that repeats itself every year, mostly out of our view.
While this year's northern hemisphere avian flu epizootic has largely wound down, billions of migratory birds will begin to head south again in a little over 3 months, giving us our first glimpse of what avian flu did on its summer vacation.
