#3898
imported_Martin
Participant

Hi Les:

Thank you for another informed post.

Haven’t had time yet to read the FAO document (60 plus pages I noticed!).

I’d thought China was using vaccine against H5N1 before use really sanctioned by FAO – and FAO had been leery re poultry flu vaccines (broadly, emergency use only).
“The current virulent strain of H5N1 emerged among vaccinated poultry in China.” said New Scientist
http://www.newscientist.com/article.ns?id=dn7338

Now, seems emergency is throughout China’s poultry industry.

Quote:
China’s Ministry of Agriculture said in Beijing on Monday that the country now produces more than 100 million doses of bird flu vaccine every day, which can meet the demand in major areas for epidemic prevention and control.

A press release on the ministry’s website says the ministry has enhanced the research, manufacture and quality supervision of bird flu vaccine to guarantee supply.

The ministry also enhanced crackdown upon counterfeit vaccines and issued 8.2 million fake-proof labels for this purpose.

http://english.people.com.cn/200511/15/eng20051115_221239.html

Might a virus strain that can thrive in vaccinated poultry also evolve to high virulence, compounding problems with H5N1?

Not that always need a virus strain that thrives with good vaccine, when there can be problems with counterfeits, and other bad vaccines in China. In 12 November South China Morning Post, a news item started:

Quote:
Drugs salesmen who smuggled out an unlicensed
vaccine still being tested and sold it on the market have been blamed
for the massive outbreak of bird flu in Liaoning province.

Says many farmers in Heishan county had used a vaccine produced by
Inner Mongolia Jinguu Group, and this offered little protection against
the deadly disease. The vaccine was intended for testing, but not
supposed to be sold.

In a Nature commentary, Robert Webster and Diane Hulse argue for use of good poultry vaccines coupled with sentinel birds. But using vaccines isn’t straightforward, partly as also get sub-standard vaccines:

Quote:
The few comparative tests that have been done on agricultural vaccines from different suppliers show that some are good and some are bad. Bad vaccines prevent the symptoms of disease but not virus excretion, which can lead to later infection. One of the many arguments against the use of agricultural vaccines is that they promote the selection of mutations in the circulating virus, perpetuating the risk of infection either in the original species or in others.

Controlling avian flu at the source

As well as China, Indonesia has adopted poultry vaccines, yet:
Indonesia says some poultry vaccine below standard

Vietnam in U-turn over bird flu vaccination is a New Scientist news item from May – about Vietnam about to start large-scale testing of poultry flu vaccines.

This article notes that Thailand allows vaccination only for fighting cocks, and free range ducks and chickens. Yet, I’ve seen reports of poultry vaccines smuggled into Thailand:
Thailand finds 2 million doses of bird flu vaccine smuggled in (26 Feb 2004 report)

So, it now seems you’re damned if you vaccinate, damned if you don’t.

With today’s poultry farms evidently serving as “disease factories” (as termed by science writer Wendy Orent) – where Paul Ewald’s theory re evolutionary biology predicts virulent strains of flu will evolve [and can persist while very sick birds can readily transmit disease], it seems the nasty H5N1 variant will remain with us.
Halting vaccination, coupled with fully effective culling (yes, this failed in Vietnam, so hardly hopeful) just might prove a short, extremely sharp shock that could eradicate it – like Hong Kong in 97, but on a massive scale.

Otherwise, need radical transformation of poultry farming – so very sick birds can no longer readily transmit H5N1 and other virulent flus. Something more like wild situation, where dead ducks don’t fly.

A shocking notion, now people hooked on apparently cheap chicken.
Yet Prof Peter Singer notes that we’re seeing something of the true costs of our chicken farms, in
`Factory farming’ is unnatural, unsustainable and dangerous

Post edited by: martin, at: 2005/12/11 00:55