While the spread of the H5N1 virus to Europe is a serious issue for farming and wildlife, it presents a negligible threat to human health that should not worry the public, Professor Sir David King told The Times.

experience of the disease in Asian countries suggests that individuals are about seven times more likely to win the national lottery than they are to contract bird flu.

In China, where the disease is endemic among birds, just 14 infections and 8 deaths have been confirmed by the World Health Organisation in a population of 1.3 billion people — a rate of one case per 93 million and one death per 163 million.

This suggests that the current form of the virus is so difficult for humans to catch that the risk will remain extremely remote even if it infects British birds, as is likely now it has spread to France and Germany.

Britain’s population is 60 million, making even a single case unlikely at these odds.

Speaking exclusively to The Times, Sir David said that the public health threat from the virus had been widely exaggerated, and confused with the danger it posed to the poultry industry.

“It is very important to keep things in proportion, and to make a distinction between the virus in birds and the virus in humans,” he said.

“Your chances of winning the lottery are about 1 in 14 million. Your chances of catching bird flu are more like 1 in 100 million, even if we had H5N1 among the chicken population in Britain.

“That’s a back-of-the-envelope calculation based on China, but the real figure will not be much different. It may in fact be even lower than 1 in 100 million, because we don’t live cheek-by-jowl with chickens in the same way. Simply put, this is not an issue we should worry about in terms of public health.”

From a human health point of view, he is more concerned about the spread of H5N1 into Africa, where cases have now been confirmed in birds in Egypt, Nigeria and Niger.

These developing countries lack the resources to contain the disease, and have backyard poultry flocks similar to those found in the Far East, which expose large numbers of people to the virus. This creates potential crucibles for genetic mutations that could allow the virus to start spreading from person to person, a critical event for a pandemic.

His comments were backed by Neil Ferguson, Professor of Mathematical Biology at Imperial College, London, one of the world’s leading influenza epidemiologists. He said that the risk of human cases in Britain was “absolutely negligible”.

“There have been about 150 infections in South-East Asia and China, and the population size of the heavily affected region is around the 300 to 400 million mark,” Professor Ferguson said. “Whether it is 1 in 100 million or 1 in 10 million, it is a very small risk. … The risk is absolutely negligible, though convincing people of that is difficult because H5N1 has now acquired a rather mythological status.”

Susanne Glasmacher, of the Robert Koch Institute in Berlin, which leads Germany’s bird flu containment efforts, would not estimate the risk of human infections in the country, where 136 dead birds and a cat carrying H5N1 have been found. Any risk, however, is likely to be lower than in Asia. “The virus in Asia was passed on overwhelmingly to poultry farmers and those living in very close daily contact with birds,” Dr Glasmacher said. “In Germany we have different lifestyles.”

Britons ‘far more likely to win the lottery than to contract avian flu’