Saturday, January 24, 2015

Hong Kong CHP Update On Imported H7N9 Case



# 9623

We’ve an update on the epidemiological investigation into Hong Kong’s second imported H7N9 case of the season, and some comments from CHP Director Dr. Ko Wing-man over concerns that the H7N9 virus could evolve into a more dangerous virus..

Update of imported human case of avian influenza A(H7N9)

The Centre for Health Protection (CHP) of the Department of Health (DH) today (January 24) reported the latest updates of the second imported human case of avian influenza A(H7N9) in Hong Kong this winter, and again urged the public to maintain strict personal, food and environmental hygiene both locally and during travel.

So far, seven close contacts and 62 other contacts have been identified.

(A) Close contacts

The close contacts have been put under quarantine and prescribed with antiviral presumptive treatment until the completion of the five-day treatment or 10 days after last exposure to the patient, whichever is earlier. They include:

  • Two family members who remained asymptomatic;
  • An in-patient admitted to the same cubicle as the patient in the Accident and Emergency Department of Alice Ho Miu Ling Nethersole Hospital (AHNH), who was symptomatic and tested positive for Influenza A (H3) virus; and
  • Four asymptomatic patients who had attended the private clinic in Tai Po with the patient.

(B) Other contacts

The other contacts have been put under medical surveillance and they include:

  • 34 asymptomatic healthcare workers who took care of the patient in AHNH;
  • 24 clinic contacts (including patients and staff of the clinic in Tai Po) in which one was symptomatic and tested positive for Influenza A (H3) virus while the rest being asymptomatic;
  • An immigration officer involved upon patient's arrival in Hong Kong, who was symptomatic and tested negative for Influenza A; and
  • Three asymptomatic ambulance officers involved in patient transfer.

The Lady MacLehose Holiday Village in Sai Kung under the Leisure and Cultural Services Department is being converted as a quarantine centre. Asymptomatic close contacts will be quarantined there.

Investigations are ongoing.

The CHP's hotline (2125 1111) for public enquiries will operate from 9am to 6pm today and tomorrow (January 25).

Ends/Saturday, January 24, 2015
Issued at HKT 19:48


With China’s winter epidemic of H7N9 ramping up, and seasonal H3N2 in full swing, Hong Kong’s CHP Director Dr. Ko Wing-man has publicly expressed concerns over the possibility that this emerging avian flu could evolve into a more dangerous virus. 


First a couple of brief media reports on his concerns, then I’ll return with a bit more.


Ko Wing-man worried about the bird flu virus variants

Secretary for Food and Health, Ko Wing-man, said the second case of human infection appeared in Hong Kong H7N9 bird flu cases, patients have no contact with live poultry, only to over-selling live poultry markets, the citation to these places, there will be the risk of infection, subject to appeal to the public if the visiting birds flu-affected areas, in addition to not touch live poultry, also not to the sale of live poultry locations.

Ko Wing-man said, scientists fear the high incidence of seasonal flu, plus the H7N9, may lead to two viruses in animals or humans cross-infection, the virus appears to make genetic changes, the authorities are very concerned that if a new virus appears, it will immediately for research. Ko Wing-man said, did not receive notice Mainland authorities, resumption of live chickens to Hong Kong, in Hong Kong and mainland cities to Hong Kong chickens and quarantine departments to maintain close liaison.


Hong Kong suffered a bird flu fear flu virus genetic changes
2015-01-24 United Daily News reporter Li Chun ╱ immediate reports

Hong Kong suffered a bird flu seasonal influenza, Hong Kong Secretary for Food and Health Ko admitted that fear there will be changes in the viral genes.


With the same time, a time when the peak of the flu in Hong Kong, 27 people have died in the past week, the new flu, the occupancy rate increased intensive care unit of public and private hospitals. Ko means worrying situation, appealing for influenza vaccination.

Change and adaptation are the hallmarks of all influenza A viruses, but we worry most about novel viruses (like H7N9, H5N1, H10N8) because of their ability to cause severe, often fatal illness in humans. 


Of the novel  viruses currently on our radar, H7N9 seems to be furthest along the path towards mammalian adaptation, and research shows continued evolution over the first two epidemic waves. 


Last summer, in Eurosurveillance: Genetic Tuning Of Avian H7N9 During Interspecies Transmission, we saw a study that identified at least 26 different genotypes of the virus in circulation.  The authors warned:

Overall, due to the genetic tuning procedure, the potential pandemic risk posed by the novel avian influenza A(H7N9) viruses is greater than that of any other known avian influenza viruses.


While there have been fewer than 500 H7N9 cases recorded to date, there are some estimates that put the real number of symptomatic cases in the tens of thousands (see Clinical severity of human infections with avian influenza A(H7N9) virus, China, 2013/14).

Assuming there really are a sizable number of mild cases going undetected, that would increase the chances of seeing a reassortment during this heavy seasonal flu season, with unpredictable results.



Reassortment is the mechanism where two different flu viruses infect the same cell simultaneously, and swap genetic material, producing a new, hybrid virus. -  Credit AFD


Admittedly, no one knows how likely this is to happen – or even if an H7N9/H3N2 reassortant would be viable. But since this process has the potential to produce a dangerous hybrid without warning, it remains a genuine concern. 


This isn’t the only evolutionary path that H7N9 could take towards becoming a pandemic virus. It could simply pick up host adaptations as it passages through humans, it could reassort with other influenza viruses in a non-human host, or it could accrue the requisite mutations through antigenic drift


Alternatively, there could be some unknown species barrier that prevents avian flu viruses from ever posing a pandemic threat to humans (see Are Influenza Pandemic Viruses Members Of An Exclusive Club?).

While that would certainly be welcome news, few researchers at this point are willing to bet the farm on our being that lucky.

No comments: