One of the most important avian migratory pathways in the world is the East Asian- Australasian Flyway (EAAF), which is described (below) by the EEAFP (East Asian-Australasian Flyway Partnership), which monitors the arrival and health of migratory birds along the route each year.
The East Asian - Australasian Flyway (EAAF) stretches from the Russian Far East and Alaska, southwards through East Asia and South-east Asia, to Australia and New Zealand and encompasses 22 countries. The EAAF is home to over 50 million migratory waterbirds from over 250 different populations, including 32 globally threatened species and 19 Near Threatened species.Although it has been the source of excitement and wonder for bird lovers every fall for uncounted eons, in recent years the annual southbound trek of migratory birds has also been associated with the arrival and spread of HPAI and LPAI viruses.
While once the topic of heated debate (see Bird Flu Spread: The Flyway Or The Highway?). the role of migratory birds in the long-distance spreading avian influenza is now pretty much settled. Despite protestations that `sick birds don't fly', we now know that many avian species can carry HPAI viruses asymptomatically.
A study, published in 2016 (see Sci Repts.: Southward Autumn Migration Of Waterfowl Facilitates Transmission Of HPAI H5N1), posited that waterfowl can pick up new HPAI viruses in the spring (likely from poultry or terrestrial birds) on their way to their summer breeding spots - where they spread, amplify, and potentially evolve - only to redistribute them on their southbound journey the following fall.
Which means that nations that lie beneath the major migratory flyways begin to sound the alert each fall for poultry interests to beef up their biosecurity. We've already discussed concerns over avian influenza's return this fall to Europe (see FLI Risk Assessment: Avian Flu Threat High For Germany & Europe This Fall), but the threat is very much presemt in Asia as well.
Today South Korea's MAFRA issued the following (translated) alert on the early, and heavy arrival of migratory birds to the Korean peninsula, warning that now is the time to begin increasing biosecurity efforts.
Winter migratory birds begin to arrive in earnest, strengthening poultry farms(Continue . . . )
2021.09.29 10:58:59
The Ministry of Agriculture, Food and Rural Affairs (Minister Kim Hyun-soo, hereinafter referred to as the Ministry of Agriculture, Food and Rural Affairs) announced that it will strengthen the avian influenza prevention management of poultry farming farms and migratory birds across the country as a result of a recent survey of the early arrival of winter migratory birds conducted by the Ministry of Environment (Minister Han Jung-ae).
❍ The early bird status survey of migratory birds in this winter was conducted by the National Institute of Biological Resources under the Ministry of Environment on 10 major migratory birds in Gyeonggi and Chungcheong Province for three days from Sept. 24 to Sept. 26, 21, and confirmed 38,927 birds of 83 species.
❍ Compared to last year's survey, the total population increased by 37.7%*, and in particular, ducks and geese increased by 82.5%**.
* Overall Current Status: ('Sep.) 36,309 → ('Sep.) 28,277 → ('Sep. 21) 38,927
** Status of Ducks and Geese: ('September 20) 15,714 → ('September 21) 28,685
This year, the number of highly pathogenic avian influenza in foreign wild birds has increased sharply compared to last year, and in particular, the virus type has become more active*, which is likely to lead to various high pathogenic avian influenza in Korea through migratory birds this winter.
* Wild bird detection (until August 1∼8): (Europe) '31 in 20→ '1,237 in 21, (Asia) '14 in 20 → '44 in 21
** Serum type: (Europe) '20 Year 1→ '21 Year 6 Species, (Asia) '20 Year 3 Species → '21 Year 4 Species
❍ The Ministry of Agriculture, Food and Rural Affairs and the Ministry of Environment will keep a close eye on the arrival of migratory birds this winter, and will preemptively implement quarantine management, such as controlling the access of livestock vehicles to migratory birds*, inspection of migratory birds' feces**, and disinfection, during the special quarantine period for livestock epidemics (from October to February) even if avian influenza does not occur.
* ('19) 84 points → ('20) 234 → ('21) 260 ('11%↑ over 20)
** Target migratory birds: "103 places in 20 years → "109 places in 21 years (6 certificates)
The Ministry of Agriculture, Food and Rural Affairs requested that all poultry farms in the country thoroughly follow quarantine rules to prevent the outbreak of avian influenza at a dangerous time when migratory birds begin to arrive.
❍ Emphasizing the strict implementation of the ban on outsiders from entering poultry-keeping facilities and visiting migratory birds.
❍ In addition, the government urged the government to thoroughly overhaul quarantine facilities such as nets and electric rooms and comply with anti-avian influenza prevention rules such as changing boots (shoes) for each barn and disinfecting the inside and outside of the barn.
Considerably further down the flyway, Taiwan is also warning on the imminent arrival of this fall's migration.
A confirmed case of avian influenza in Yunlin Gukeng White Broiler Breeder Farm, and implement epidemic prevention measures in accordance with standard operating procedures110-09-28The Animal and Plant Inspection and Quarantine Bureau (Bureau of Inspection and Quarantine) stated today (28) that the Animal Health Laboratory notified that the white broiler breeder farm in Gukeng Township, Yunlin County was diagnosed with H5N5 subtype highly pathogenic avian influenza (active notification), and it operates in accordance with the standard According to the procedures, the Yunlin Animal and Plant Epidemiological Institute executed the culling and destruction of 17,937 white broiler breeders in the farm at 70 weeks of age, and supervised the industry to complete the cleaning and disinfection of the farm. A total of 14 cases of avian influenza have been confirmed and culled in poultry farms since 110 (6 farms of land poultry, 7 farms of geese and 1 farm of ducks).
The Bureau of Inspection and Quarantine stated that the H5N3 subtype low pathogenic avian influenza virus nucleic acid was recently detected in the wild bird row in South Korea, and the migratory birds have come to Taiwan for the winter season. The risk of new avian influenza viruses imported into foreign countries by migratory birds has increased. The industry should maintain the normal operation of bird prevention facilities in poultry farms, strengthen the cleaning and disinfection of the farms, and control the entry and exit of personnel, equipment, and vehicles in poultry farms or poultry houses to prevent the occurrence of avian influenza epidemics.
The Bureau of Inspection and Quarantine once again urged poultry farmers that there are still cases of bird flu poultry farms, and they should implement the various biosafety work of poultry farms in accordance with the "H5, H7 subtype poultry influenza prevention and control measures" announced by the local county and city government. Prevent the occurrence of bird flu. If a poultry farm is found to be inconsistent with the previous prevention and control measures, it will be fined up to NT$150,000 and improved within a time limit according to the regulations. If no improvement is made by the deadline, if highly pathogenic avian influenza is detected in the poultry on the farm, the poultry will be culled , According to the regulations, no compensation will be given.
Other Asian and Pacific nations and territories that will be on heightened alert this fall include Japan, Hong Kong, Vietnam, and the Philippines.
Oceans separate North & South America from both Europe and Asia, making it difficult - but not impossible - for migratory birds from either continent to carry HPAI viruses to the Americas. In 2014-2015, the United States and Canada suffered their worst Avian epizootic on record, when HPAI H5N8 arrived from Asia.
There are overlaps between the East Asian and the Pacific flyways in Alaska (see map below) which provide a legitimate route of entry for Asian avian flu viruses (see USGS: Alaska - A Hotspot For Eurasian Avian Flu Introductions).
Some past blogs on that possibility include:
EID Journal: Introduction of Eurasian-Origin Influenza A(H8N4) Virus into North America by Migratory Birds
USGS: Alaska Still A Likely Portal For Introduction Of Avian Viruses
EID Journal: Reassortment in Wild Birds in Alaska before H5 Clade 2.3.4.4 Outbreaks
For North Americans, our Arctic Refuge, where more than 200 bird species spend their summers, serves as a central hub, and funnels migratory birds south each fall via all four North American Flyways.
Similarly, although perhaps a bit more tenuously, there are overlaps between the European and North American flyways (see PLoS One: North Atlantic Flyways Provide Opportunities For Spread Of Avian Influenza Viruses), that could provide European avian viruses a plausible path to the New World.
Between 2014 and 2017 HPAI H5N8 - which originated in ducks in China - spread faster and further via migratory birds than any other bird flu virus on record. Arriving first in South Korea, then North America and Europe, then moving on to the Middle East, West Africa, and finally to South Africa.
A reminder that what happens with avian influenza in Europe or Asia can quickly become a global problem. And with the recent rise of zoonotic H5N6 in China, and the recent zoonotic status afforded H5N8, that could maker for an eventful fall and winter ahead.
Stay tuned.
