Photo Credit – FAO
# 8098
With increasing, albeit incomplete evidence of the H7N9 virus circulating in poultry in Mainland China, it is understandable that Hong Kong would like to prevent the virus from entering their territory, and infecting their poultry – or worse – people.
As the 7 million+ residents of Hong Kong consume more poultry than can be produced locally, every week a large quantity of live poultry is imported from neighboring Guangdong Province. The same province that has reported 5 human H7N9 infections in the past few weeks.
Negotiations over virus testing procedures have been underway for several weeks between mainland authorities and Hong Kong’s SFH (Secretary for Food & Health) Dr. Ko Wing-man. At issue is expanding the use of serum –or serological – testing for the virus.
Unlike PCR testing, which can detect the virus if the bird is shedding virus when the samples are taken, serology tests can tell us if the bird has ever been exposed to the virus. And that could tell us a great deal about how widespread the virus is in the poultry population. It does not, however, tell us whether the tested subject is currently infectious (it may, or may not be).
And therein lies the rub.
The powerful Chinese Ministry of Agriculture – which in the past has taken every opportunity to deny they have a `bird flu problem’ - would take a dim view of culling (or banning) `possibly not currently infected’ poultry based on a test only indicative of prior exposure.
Today, Dr. Ko Wing-man made the following comments regarding the negotiations with the mainland.
SFH on avian influenza A(H7N9)
Following is the transcript of remarks made by the Secretary for Food and Health, Dr Ko Wing-man, before attending a public function this afternoon (December 21):
Secretary for Food and Health: We are still discussing with the Mainland authorities regarding the introduction of serological test for avian influenza A(H7N9) among the imported poultry. I hope that it is at the final stage. But there are implications of introducing such a test which we have to deal with before the implementation.For example, I have repeatedly explained that although the rapid PCR test for avian influenza A(H7N9), which is currently in use, is already quite a big improvement in terms of our overall risk management, some experts feel that it is not 100% safe. The serological test will perhaps give us a clearer picture of how widespread the avian influenza A(H7N9) virus is among the poultry population, but the test itself cannot directly imply that the batch of poultry concerned is infectious. (A positive result) from a serological test does not strictly mean that the poultry batch (concerned) is infectious.
Therefore, how to dispose of the particular batch of imported poultry which is tested positive in serology investigation is a question, and it is something that we really need to have an agreement beforehand. I believe the Mainland authorities are now considering this aspect. I will give it a little bit more time.
(Please also refer to the Chinese portion of the transcript.)Ends/Saturday, December 21, 2013
Issued at HKT 19:01
In China, food insecurity breeds unrest, and so anything that threatens the national food supply is treated as a serious national security risk. For many Chinese, poultry is their only affordable source of meat protein.
With the H5N1 virus, the choice to cull was relatively easy. It killed a high percentage of the birds it infected. If you didn’t cull your flock, the virus would do it for you. And continue to spread, to boot.
But with H7N9, the virus produces little or no discernable illness in poultry. To the poultry farmer, culling means killing – by all outward appearances – perfectly healthy birds.
While the small number of human infections with the H7N9 virus would seem ample incentive to eradicate infected birds, to date, the evidence implicating poultry as the primary vector of the disease is pretty much circumstantial. We’ve no `smoking chicken’.
And so an agreement between Hong Kong and Mainland China on poultry testing has yet to be agreed upon.
Leaving us with more questions than answers regarding the rate of infection, and geographic spread, of the H7N9 virus in Chinese poultry.
