SciDev.Net

The number of deaths of people infected with bird flu in northern Vietnam has dropped from 70 per cent to 20 per cent, says the World Health Organization (WHO) office in Hanoi.

This is not necessarily a good thing, it warns. The fall in deaths could mean that the virus, H5N1, is becoming less deadly but more infectious, meaning that although fewer people die from it, it could spread farther and faster. Some scientists believe viruses use this tactic because killing people they infect would reduce their chance of infecting others.

Virus samples from northern Vietnam have been sent to the US Centers for Disease Control and Prevention to be compared with previous samples.

Although international researchers are finally arriving in Vietnam to help study the changing pattern of human infections, the UN Food and Agriculture Organization says that help is still lacking on the animal health side.

Although the number of people infected has increased, the number of infected poultry has fallen, puzzling experts. Another worry is that chickens may be developing resistance to the virus, which could help it spread undetected.

Link to full article in Science