Monday, October 19, 2015

WHO H7N9 Update – China




As mentioned on Friday in FAO Warns On H7N9 In China, we are starting to see scattered reports of H7N9 infection in Eastern China, an indication of cooler weather and likely a harbinger of the next winter outbreak of the virus.


I blogged on the first two cases (see China’s NHFPC Reports 2 H7N9 Cases In September) just a little over a week ago, and we saw yet another case reported on October 4th.

While 3 cases seems a modest start, it is assumed that only a small fraction of the total – the `sickest of the sick’ – are ever tested and identified (see Lancet: Clinical Severity Of Human H7N9 Infection). 


During the first couple of epidemic waves, China received a lot of praise for their rapid and detailed updates on cases.  We got – on a daily basis – case counts from each affected province, which generally included fairly detailed epidemiological data on each case (age, gender, med hx, exposure, etc.).  


Sadly that is no longer the case.  Instead, we must rely on (rare) media reports, occasional provincial MOH website announcements, terse end-of-month epidemiological summary reports, and follow up reports like the following, from the World Health Organization.


Human infection with avian influenza A(H7N9) virus – China

Disease outbreak news
19 October 2015

On 14 October 2015, the National Health and Family Planning Commission (NHFPC) of China notified WHO of 2 additional laboratory-confirmed cases of human infection with avian influenza A (H7N9) virus.

Details of the cases

The cases are a 55-year-old female and a 53-year-old male, with onset dates of 18 September and 21 September, respectively. Both cases had exposure to poultry and live poultry markets. No epidemiological link between the cases was reported. The cases were reported from 2 municipalities (Huzhou city and Jinhua city) in Zhejiang province.

Public health response

The Chinese Government has taken the following surveillance and control measures:

  • strengthen outbreak surveillance and situation analysis;
  • reinforce all efforts on medical treatment; and
  • conduct risk communication with the public and dissemination of information.

WHO is assessing the epidemiological situation and conducting further risk assessment based on the latest information. Based on the information received thus far, the overall public health risk from avian influenza A(H7N9) viruses has not changed.

As of June 2015, FAO reported continued AI A(H7N9) virus detections in the animal population in multiple provinces in China, indicating that the virus persists in the poultry population. If the pattern of human cases follows the trends seen in previous years, the human case number may rise over the coming months. Further sporadic cases of human infection with avian influenza A(H7N9) virus are expected in affected and possibly neighboring areas. Should human cases from affected areas travel internationally, their infection may be detected in another country during or after arrival. If this were to occur, community level spread is considered unlikely as the virus has not demonstrated the ability to transmit easily among humans.

(Continue . . . )


While H7N9 cases have all originated from China, the virus – like H5N1 and H5N8 – has been detected in wild and migratory birds (see HK Oriental Robin Tests Positive For H7N9), and so there are concerns that neighboring countries could one day be affected as well.

Additionally, H7N9 has been exported a handful of times via infected humans (see
EID Journal: H7N9 In Two Travelers Returning From China - Canada, 2015) to areas outside of mainland China.  Hardest hit, with more than a dozen cases, is Hong Kong. 

While this year’s H7N9 epidemic may simply be a repeat of what we’ve seen over the past three years – limited, and localized -  the virus continues to evolve (see EID Journal: H7N9’s Evolution During China’s Third Wave – Guangdong Province). 


Meaning – as with all influenza viruses - there are no guarantees that the virus tomorrow will behave as it has in the past.

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