A critical phase in the evolution of a bird flu pandemic could play out in China in the coming weeks, world bird flu expert Professor Robert Webster has said.
The University of Otago-educated virologist is back in Dunedin at the New Zealand Microbiology Society's annual conference this week, and said
a campaign in China to vaccinate its 14 billion poultry flock could have two quite different outcomes.
The Doomsday scenario is that the Chinese will use a poor-quality vaccine that does nothing more than force the virus to mutate into something more lethal.
"The international community has no way of knowing whether China will use a good one," Professor Webster said in an interview yesterday.
"There is a big argument that they will simply help the virus to evolve to become a human pathogen."
China has provided few details about the vaccination campaign it has begun. It is even unclear if the birds are to be vaccinated against the virulent H5N1 bird flu strain that has ravaged poultry stocks across Asia and killed at least 64 people since 2003.
For all the misgivings about the Chinese programme, he said the international community should be doing more to vaccinate animals.
"There are good vaccinations available for agriculture that aren't being wisely used."
Others were too weak, as animal vaccines were not subject to the same quality controls that applied to human vaccines, he said.
Even if the Chinese efforts did not precipitate the worst-case scenario, that could still play out somewhere else in the world, Professor Webster said.
The recent discovery of the virus in flamingoes in Kuwait indicated it was moving down towards Africa, which could provide the perfect environment for the critical mutation to human-to-human transfer.
"If it gets into the backyard flocks in Africa and people with HIV, that's a real worry," he said.
People whose immune systems were compromised by HIV, either died quickly or went on shedding the virus for weeks.
If the former happened that was tragedy, but if it were the latter, it might be even more dangerous.
"It gets the chance to adapt to the human and pick up the characteristics of receptor specificity," he said.
With that mutation, it could go on spreading human-to-human.
- OTAGO DAILY TIMES
