How bird flu could be stopped

By Caroline Ryan
BBC News Online health staff

Even healthy birds may have to be slaughtered

Avian flu is currently sweeping through Asian countries. Millions of birds have been killed in a bid to stop the disease spreading, but seven people have already died from the disease.

Health and agriculture officials from across Asia are meeting in Thailand on Wednesday to discuss what else they could do.

But experts say that the only way to stay one step ahead of the virus is to keep on culling birds which might be affected.

If that fails to happen and infected birds reach market, the disease is certain to spread.

We have seen a very small number of cases in Thailand and Vietnam. We want to ensure it stays small Ian Simpson, World Health Organization Q&A: Avian flu

People who come into contact with those birds would then be at increased risk of contracting the virus.

When Sars emerged late in 2002, doctors kept people in isolation in a bid to prevent the disease spreading.

But avian flu does not need to be treated in the same way, because the disease has not yet been passed between humans.

Hugh Pennington, professor of bacteriology at Aberdeen University, told BBC News Online: "The first line of defence is killing all infected chickens and the birds they have come into contact with.

"It's how we dealt with the foot and mouth epidemic."

'Advanced disease'

People who are in close contact with poultry are at the highest risk of contracting the disease.

Birds excrete the virus, which dries and becomes pulverised, and can then be inhaled.

Workers in the Asian poultry industry can cut their risk of developing the virus by keeping hen houses as clean as possible and washing their hands after dealing with birds.

Those who come into contact with wild birds are also being advised to wash their hands because of concern they too could be carrying the virus.

If avian flu did start to spread between humans, scientists would have the option of using antiviral drugs, such as rimantadine.

These drugs are unlikely to have been used in the Asian outbreaks so far however, both because they are expensive, and because the cases of avian flu that have come to light have been at an advanced stage, making effective treatment less likely.

But Professor Pennington said: "These drugs would come into their own if there was an epidemic."

Experts are also working on developing a vaccine which could be used if the disease did begin to spread between humans.

Black market risk

However, the World Health Organization (WHO) is working to prevent such measures ever being needed.

It will be overseeing the meeting of Asian officials in Thailand.

Ian Simpson of the WHO said: "We will be exchanging information and ensuring the cull is co-ordinated so that the risk of infected birds being sold on the black market or exported is minimised."

He added: "We have seen a very small number of cases in Thailand and Vietnam. We want to ensure it stays small."