Avian influenza experts say bird flu is traveling across the globe at much greater speed. They warn against complacency, and urge countries to implement pandemic preparedness plans without delay. Lisa Schlein reports for VOA from Geneva, where experts are meeting to assess how prepared the world is to cope with a possible pandemic.

A child walks by cage full of chickens at a poultry market in Nanjing, eastern China's Jiangsu province

The senior U.N. System Coordinator for Avian and Human Influenza, David Nabarro, says between 2003 and 2006, the deadly H5N1 strain of the bird flu virus was detected in 16 countries. He says that number has doubled in just six months.

"I would say it is certainly moving into more and more countries, with a speed that is, for me, and for my colleagues, a continuing and serious cause of concern," he said.

Another cause of concern is the high mortality rate. WHO Assistant Director General Margaret Chan says 228 human cases of bird flu have been reported in 10 countries, and 130 of them were fatal.

"Now this is, in terms of avian influenza, a very devastating disease," he said. "We have never seen, what we call, such a high case-fatality rate. That means more than…50 percent of people affected by the infection eventually succumb to the disease."

WHO says avian flu is still primarily an animal disease. Humans have become ill after direct contact with a sick bird. In recent months, there have been some limited cases of human-to-human transmission, most notably in Indonesia.

Although the risk for humans remains minimal, WHO acknowledges the H5N1 virus could mutate into a form that could spread easily among humans, causing a pandemic that could potentially kill millions.

The deputy director general of the U.N. Food and Agriculture Organization, David Harcharik, says, many countries in Asia, the Middle East and Europe have successfully stopped the spread of bird flu. They have done so by employing methods, such as the culling of sick poultry, disinfecting and vaccinating birds. Harcharik says, once H5N1 is stopped in poultry, human cases also stop.

Nigerian child holds up a chicken outside the family home in Todo village

"Of special concern is Africa, where there is a real risk of avian influenza becoming endemic in several countries, at least in the short term," he said. "One reason is that, it is very difficult to enforce appropriate control measures in the African context. Culling, compensation to farmers and effective checks on animal movements, which have worked well in Europe and East Asia are much harder to achieve in Africa."

Harcharik says another worry is the illegal poultry trade in Africa. He says the movement of poultry and poultry products across borders is one of the main vehicles for spreading the virus. He warns the risk will remain until effective control is achieved.