Another person has died in Vietnam from avian influenza. The World Health Organization Bird flu has now confirmed five deaths, while Vietnamese officials have blamed bird flu for the loss of another nine lives.
A massive cull of poultry is continuing, with about two million birds now slaughtered or killed by the virus. However, WHO officials are warning that the workers carrying out the slaughter may themselves be vulnerable to infection.
“There are some reports that these people need more protection,” says spokesman Dick Thompson at WHO headquarters in Geneva, Switzerland. “They may be wearing gloves and masks, but they should also be wearing eyewear.”
The virus – A(H5N1) – is largely transmitted via bird droppings when particles are stirred up by a breeze and inhaled. It is very rare to contract the disease by eating cooked contaminated meat.
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Workers who find themselves in paddocks crowded with nervous, flapping birds are likely to be exposed to large amounts of contaminated dust, Thompson told New Scientist, making eye protection highly advisable. In another outbreak of highly pathogenic avian influenza in the Netherlands in April 2003, there were over 70 cases of eye infections.
Double danger
So far all the human victims are thought to have caught the virus directly from birds, rather than from another person. The major concern for health officials is that a person catches both avian and human flu viruses at the same time, particularly as it is now the human flu season in northern Vietnam.
The two viruses could combine to produce a hybrid that was both highly pathogenic and transmissible between humans. Such viruses are thought to have caused pandemics in the past.
It is not known whether the virus is being carried around by wild birds, which are monitored for flu in Europe and North America but not so far in Asia. Normally flu viruses form a reservoir in ducks – but this strain of H5N1 virus kills ducks, a shift in virulence that has unsettled virologists.
However, Thompson notes that the avian virus is not transmitted very efficiently to humans: “There could be a million birds or more in Vietnam that have the disease or have had the disease, and yet we have just a handful of [human] cases.”
Flu expert John Oxford, of Queen Mary’s School of Medicine in London, UK, is also cautiously optimistic, saying that a virus capable of causing a pandemic would probably have arisen already if was going to.
But he adds that the huge migrations of people that accompany the Chinese New Year will provide a crucial test. “If we can get past this week without a major outbreak of H5N1, or SARS, then I think we can relax a little,” he said.
