• Sat
  • Dec 27, 2014
  • Updated: 7:52am
H7N9 avian flu

Poultry trade may be spreading killer H7N9 virus

Expert called in by WHO recommends a review of market practices in China and Asia

PUBLISHED : Monday, 06 May, 2013, 12:00am
UPDATED : Monday, 06 May, 2013, 7:06am

Poultry workers moving between wet markets and farms are probably responsible for the wide geographical spread of the deadly new bird flu virus on the mainland, says a Hong Kong expert invited by the World Health Organisation to investigate the outbreak.

Cages, vehicles and personnel handling birds were likely to be taking the H7N9 virus with them as they moved around, spreading the disease to many provinces, Malik Peiris, a professor of virology and medical science at the University of Hong Kong, told the South China Morning Post.

"It is likely that the spread is predominately through the poultry trade … it seems much more practical [that it spreads] with the route of poultry movement."

In 2002, contaminated poultry cages carried from markets to farms proved to be a key factor behind the H5N1 outbreak in Hong Kong. Peiris said such traffic was likely to be "one important risk factor" in how the new virus is spreading.

Since H7N9 was first identified on March 30, 127 cases have been detected in 10 provinces, the latest being a 69-year-old farmer in Fujian . Twenty-seven people have died.

The Ministry of Agriculture said yesterday that a chicken sample from a wholesale market in Dongguan had tested positive for the virus - a first in Guangdong, although there have been no human cases in the province. The finding highlights the growing risk of the disease spreading to Hong Kong.

Peiris said: "It may be a good time for China and Asia to review their poultry practices … and Hong Kong can act as a model in terms of its good biosecurity measures."

The most practical step to reduce health risks was to close wet markets, as this would not only stop human infections but also stop the disease from spreading among farms, he said.

"There are still many unanswered questions, such as the mechanism [in] the virus that allows it to attack humans, the mutation responsible, [and] what it takes to make human [-to-human] transmission possible."

Peiris said a large-scale study of blood samples would be conducted on the mainland to check whether there have been hidden "silent infections" of H7N9 in the larger population - a key factor in determining if the virus can be spread between people.

"As time passes, there may be a bigger chance of the virus changing and adapting, and transmitting human to human."

Peiris said the survey intended to find out if it was possible for people to be infected with H7N9 and develop only mild symptoms - cases that are never detected or reported. But he would not disclose more details of a report the WHO submitted to the mainland authorities. He said the evidence so far suggested that wet markets were where the new virus had mutated and jumped to humans.

But he said if H7N9 stemmed from chickens rather than other poultry or wild birds, it might be "extremely difficult to get rid of it" on the mainland due to the popularity of chicken as a food.

View H7N9 map in a larger map

Click on each balloon for more information on individual patients infected: blue, patients infected with the H7N9 virus under treatment; red, those infected with H7N9 who have died; yellow, those who have fully recovered; and pink, those infected other types of the Influenza A virus, including H1N1.


More on this story

For unlimited access to:

SCMP.com SCMP Tablet Edition SCMP Mobile Edition 10-year news archive



This article is now closed to comments

The only way to stop this mass killer when it eventually emerges is to address it at 'source' for this is the only way to stop this human-to-human killer virus. Why does the world contend that a vaccine will come in time? Because Big Pharma says it will. This is the biggest lie of all time and where because governments are like sheep and accept this premise, 100s of millions will die this next time around. Margaret Chan has said many times that it is only a matter of time not when. The only strategy that has worked and stopped the killer virus in its tracks in 1997 was - ****avian-influenza.cirad.fr/content/download/1931/11789/file/Kennedy-F-Shortridge.pdf

When will the world wake up and see that only by addressing the virus at its 'source' will we stop several hundred million dying - The ‘prevention is better than cure' strategy and not the ‘let it happen and then we will try to cure it’ strategy, like the mindset we have presently. We have to turn that thinking around and use the same strategy as was used in Hong Kong in 1997 and kill the virus in its tracks.

Are we so dumb to believe Big Pharma and that a vaccine will come in time. Apparently we are and where the time horizons for the Spanish Flu that took up to 100 million lives and the 2009 Swine Flu pandemic response where a vaccine came four months after in time that the Spanish Flu did its worst. Indeed only after 7 months 1 week from the first human-to-human death was the vaccine actually authorized by
I appreciate all comments, however what it is most important is possible mutation of virus causingso human-to-human transmission. Any variant of the virusH7N9 can be evem more lethal than this one.Another pointis possible resistance to neuroinimidase agents and/or limited supply of these drugs . All aspects should be considered.
No doubt that travelling birds are at the centre, but the solution proposed in this report to close the wet markets is at the very least reckless. The perils of an agri-food supply chain dominated by supermarkets is well documented in the west. There are rises in rates of obesity and other diet related illness because value added foods (the ones with e-numbers and high salt, fat, sugar content) are pushed at consumers. When we are distanced from food suppliers there is no guarantee that we are getting the food we think we are getting (e.g., horse instead of beef, rat instead of lamb, tainted pork). Rates of food waste increase because of the way food is sold in specific, pre-packaged units.
Consider the poor. Supermarkets sell in set amounts. Those in subdivided or cage housing have shopping patters that are different to that catered for by the supermarket because storage and income is limited. The poor depend on the relationships that they have with the markets.There are handouts and discounts made possible in the markets. Food is cheaper. People can eat in ways that are more healthy.
That is just from the consumption perspective.
If we consider the supply perspective the issues increase. When we prioritise systems dominated by large corporations the pressure on farmers increases. We end up with GMO foods dominating the landscape and monoculture farms, which is both economically and environmentally problematic.
Farm focused solutions are a better bet.
Professor Peiris is a virologist with sterling credentials. He is the quintessential expert. Being only an informed layman, I agree with what he is saying here. They seem to confirm my hunch about this new H7N9 strain.
However, I am still waiting for the definitive conclusion by expert epidemiologists after their complete analysis of the disease vector trajectories.
Since this H7N9 strain has so far been revealed non-transmittable among humans, SCMP should start easing up its Chicken Little alarmism.
The 2009 H1N1 swine flu in the US took 11,600 lives. It is estimated that 55 million were infected. As influenza A goes, it's nothing to get excited about. The initial over-reaction in the US was due to the ignorance of the number of people that were infected. Thus the original guesstimate of death rate was order of magnitude higher. As usual, the media greatly sensationalized the potency of this pathogen.
Given Hong Kongers' low level of knowledge in medicine and public health, and worse, and their poor judgment in filtering out inaccurate media information, it's important news reporters and commentators not to exaggerate this virus risk when an epidemic is far from palpable.
As usual, we can expect commentators with a China bashing agenda pointing accusatory fingers at mainland health authorities.
Just remember, many aged and immune compromised die from the run of the mill influenza A. Worse familiar strains are transmittable among humans.
Alas, when H7N9 arrives in Hong Kong - and it will, we will wonder why the central abattoir proposal was abandoned. We have had so much to prepare, but our memory is short, and the special interest groups have too much power...


SCMP.com Account