The avian influenza virus is unlikely to cause a pandemic among humans, experts attending the APEC Symposium on Emerging Infectious Diseases said yesterday.

Although the virus has killed more than 100 people around the world, it's not spread easily between people, said Zeng Guang, chief epidemiologist of the Chinese Center for Disease Control and Prevention (China CDC).

So far 16 cases of human infection have been reported in China. "We've found that some of the patients had immune deficiencies and two were pregnant," Zeng said.

The reason why they were infected remains unclear, but "We know that humans are not generally susceptible to the virus," Zeng told China Daily at the two-day APEC symposium, which opened in Beijing yesterday. Most of the human cases in China had direct contact with diseased poultry.

Although realistically it's likely that large numbers of people have come into contact with diseased poultry, only "a very small number" of them were infected by the virus. This means the virus isn't spread by airborne particles, said Henk Bekedam, representative of the World Health Organisation (WHO) in China.

If it could be spread through the air it's impossible that there are less than 200 human cases in the world, Bekedam noted.

After taking samples from healthy people living with infected people, Zeng said, "We found the virus in respiratory systems of some of those tested." However, the virus in the respiratory system "cannot really infect the person," he added.

This is because people are not susceptible to the virus now whether it is carried by poultry, animals or humans, he observed.

Both Zeng and David Nabarro, senior UN system coordinator for avian and hunan influenza, said there are no people who have been infected with the virus but showed no symptoms.

Nabarro appreciated China's efforts to fight the deadly disease. He said China has contributed to the international effort against bird flu by achieving great progress in preventing and controlling the disease in the country. He added that the UN is expecting China with its experience and knowledge to make a greater contribution to the global fight against bird flu. 

Bekedam noted that information sharing should go on in all countries. "We hope China can share more information and samples of bird flu rapidly, regularly and globally," he said.

Wang Yu, director of China CDC, disclosed at the symposium that China would provide four samples of human bird flu virus to the WHO -- the second such contribution from the country.

"The handover is still in process," Wang said.

China forwarded two bird flu virus samples along with other virus information to the WHO in December.

Wang said laboratory tests of China's human victims show there have been no mutations involving the deadly H5N1 strain of avian flu.

(Xinhua News Agency, China Daily April 5, 2006)