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While it slowed much later this summer than in the past, H7N9 activity has finally been reduced to a trickle in China, although two human cases were reported last Friday in far western Xinjiang Uygur Autonomous Region.
This welcomed lull will probably end later this fall once the weather turns cooler.With this sharp drop in human infections, China's main focus has switched to deploying a new (H5 + H7) poultry vaccine, one they rolled out last July (see China MOA Orders HPAI H7N9 Vaccine Deployed Nationwide This Fall).
The decision to add an H7 component to their existing poultry vaccine only came after a new, highly pathogenic strain of H7N9 emerged in Gaungdong Province last December, and over the spring began moving north.
Unlike LPAI H7N9 - which does not visibly sicken or kill birds - HPAI H7N9 has a high mortality rate in poultry.Over the first six months of 2017, the FAO tracked the spread of this new HPAI H7N9 virus:
Highly pathogenic virus findings: The H7N9 highly pathogenic avian influenza virus was detected in a total of 48 poultry or environmental samples (37 chickens, 1 duck and 10 environmental samples) from 23 live bird markets (LBMs) in: Fujian (Longyan City), Guangdong (Dongguan, Guangzhou, Huizhou, Lufeng, Meijiang, Meizhou, Zhongshan Cities and Haifeng County), Hunan (Chenzhou City) and Guangxi (Guilin City) Provinces;
and from 8 farms in: Guangxi (Guilin City), Hebei (a chicken layer farm in Xingtai City [reference]), Henan (a chicken layer farm in Pingdingshan City [reference]), Hunan (backyard in Chenzhou City and a large chicken layer farm in Yongzhou City [reference]), Shaanxi (a chicken layer farm [reference]), Tianjin (a chicken layer farm [reference]), Inner Mongolia (two chicken layer farms in Hohhot and Baotou Cities [reference 1, reference 2] and Heilongjiang (a chicken layer farm in Shuangyashan City [reference]) Provinces.Now, whenever we see the combination of unusual poultry mortality and a positive H7N9 lab test, the suspicion is high that HPAI H7N9 is at work - although requires additional lab tests to confirm the presence of the HA cleavage site mutation that is used to differentiate HPAI from LPAI.
Out of the 1584 confirmed human cases, H7N9 virus isolates from 25 human cases (including one from Taiwan Province) were found to be highly pathogenic for chickens.
Which brings us to the following report describing a symptomatic H7N9 outbreak in Anhui Province with excess mortality.We'll have to await further lab confirmation before this outbreak can be officially labeled HPAI.
Chuzhou Quanjiao occurred in poultry H7N9 flu epidemic has been effectively controlled at present
Date: 2017-08-25 17:11 source:
August 17, Chuzhou City, Anhui Province Quanjiao veterinary authorities found a broiler farms appear in the monitoring of suspected bird flu symptoms, the incidence of 1368, 910 died. August 18, animal disease prevention and control center in Anhui diagnosed as suspected H7 subtypes of avian flu.
August 24, by the National Avian Influenza Reference Laboratory confirmed the outbreaks as H7N9 flu. After the outbreak, according to the relevant local prevention plans and technical specifications, adhere to the prevention and control law, science and prevention and control, really good job epidemic disposal, have been culling and safe disposal 74 463 poultry. Currently, the outbreaks has been effectively controlled.
While HPAI H7N9's ultimate impact (and that of the vaccine) remains unclear, we are starting to learn more about this new HPAI variant:
- In early May in Eurosurveillance: Biological Characterisation Of (HPAI) A(H7N9) Viruses In Humans, we learned that HPAI H7N9 virus retains the ability to infect both birds and humans, and in fact, appears to be potentially slightly more infectious in both than the LPAI version.
- Two week later, in EID Journal: 2 Expedited HPAI H7N9 Studies, we saw the first detailed reports on China's HPAI H7N9 human infections - and while their numbers (n=8) remained low, making it difficult to draw any conclusions - there were already concerns this HP variant might be slightly more pathogenic in humans.
How long will H7N9 remain just China's problem?A threat which Russia - which continues to deal with their own HPAI H5N8 woes - is keenly aware of (see China's Nervous Neighbors).
