Friday, March 24, 2017

China MOA: High Mortality In Poultry Infected With H7N9 In Hunan Province

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UPDATED 1500 hrs: OIE Confirms HPAI H7N9 In Hunan Province


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For nearly four years - since H7N9 first emerged in China in the spring of 2013 - its most unusual feature was its low pathogenicity in birds (LPAI) yet its ability to produce severe, even life threatening illness in humans.

Unlike the HPAI H5 viruses - which dramatically impact poultry - LPAI has been a `stealth virus' in chickens, geese, and ducks. Often our first sign of trouble comes only after a human in contact with healthy-looking birds falls ill.

Last month (Feb 18th) China announced the discovery of two patients in Guangdong Province infected with a newly discovered highly pathogenic (HPAI) variant of H7N9 (see Guangdong CDC: Two H7N9 `Variants' Isolated From Human Cases). Additional HPAI samples were isolated in local poultry. 

The following day, we also saw the Taiwan CDC: January's Imported H7N9 Case Carried HPAI Mutation. All three cases showed signs of antiviral resistance, although it wasn't clear if that developed after they received treatment.

All HPAI H7N9 reported to date have been in Guangdong province, and so its `fitness' to spread further remains unknown. Although our knowledge of this new mutation is limited, for now we've no evidence that it substantially increases the risk to humans (see ECDC Comment On HPAI Mutation Of H7N9).
All of which brings us to a report from China's Ministry of Agriculture detailing a recent outbreak of H7N9 in Hunan Province which resulted in observable morbidity and substantial mortality in poultry.

Both atypical of LPAI H7N9 outbreaks. 

Today's dispatch opens by stating the importance of following up on the H7N9 influenza virus mutant strains - a pretty good idea of what they are thinking - but it never directly refers to this outbreak as HPAI.  A genetic analysis of the HA gene is required to confirm HPAI - and perhaps they are waiting for that - but this outbreak has all the outward appearances of high path bird flu.

Hunan province lies adjacent - and to the north and west - of Guangdong province. Hunan province reported 5 human cases last Friday, and 4 human cases today (onsets go back to early March) making it one of the more active regions these past two weeks.

Any indication that HPAI H7N9 is on the move (possibly via migratory birds) would be an important finding. But whether LPAI or HPAI, the H7N9 virus continues to evolve, and so we must remain ready for surprises. 

Hopefully we'll get a more definitive report (and genetic analysis) on this outbreak in the days to come (see update).

Hunan Provincial Department of Agriculture veterinary guidance departments earnestly poultry H7N9 influenza prevention and control
Date: 2017-03-24 17:58 Author: Source: Ministry of Agriculture Information Office

For some of the recent detection of H7N9 influenza virus mutant strains, the Ministry of Agriculture attaches great importance to the timely follow-up, on the basis of preliminary work, to guide the local animal husbandry and veterinary departments to further carry out targeted prevention and control work. All in accordance with the requirements of a good grasp of monitoring and emergency treatment, the detection of pathogen positive or the outbreak of the farm households poultry, and resolutely culling and harmless treatment, the timely elimination of risks.

March 19, Yongzhou City, Hunan Province, Dong'an County Veterinary Department in the monitoring found that some farmers raised breed chickens suspected bird flu symptoms, the incidence of 29,760, only 18,497 died.

March 20, Hunan Province, animal disease prevention and control center diagnosed as suspected avian influenza epidemic. March 24, by the National Avian Influenza reference laboratory confirmed the outbreak for the H7N9 flu epidemic. After the outbreak of the epidemic, the local start of the plan, in accordance with the technical specifications to prevent the epidemic disposal work, has been culling and harmless treatment of 171179 poultry. At present, the epidemic has been effectively controlled.

 

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