The World Health Organization (WTO) warned Thursday that it is too early to tell if the avian influenza in China is under control, adding that prevention and detection measures should be stepped up.

Dr. Shigeru Omi, WHO's Western Pacific regional director, made the remark during a visit to the home of a nine-year-old boy in central China's Hunan Province who survived a bout of the flu. He was China's first human case of H5N1.

"It is too early to say if it is under control," said Dr. Omi. "I will not be surprised if we have more human cases during the winter months."

He said bird flu outbreaks in December, January and February, can be much more serious.

So far, China has reported two deaths among six human cases of bird flu in Hunan, Anhui, Guangxi, Liaoning and Jiangxi provinces.

"Based on the experiences from other countries, the number of cases will drop and then rise again," said Dr. Omi.

"A temporary reduction in the number of cases doesn't mean the circulation of the virus has been halted. We have to assume that the virus is still circulating. That the virus is still there in the environment at least among chickens and ducks," he said.

He warned that the highly pathogenic avian influenza virus is very unpredictable and unstable and could mutate into a form that can pass easily between people, leading to a human pandemic.

"We have to assume that it is impossible for this virus to become so infectious that a global pandemic might happen," he said. "We are very concerned about the possibility this virus can efficiently transmit human to human."

"We don't know when it will happen," he said. "But we have to prepare for the worst situation, and the international community has to do its utmost to try to avert or prevent it."

Vietnam, Thailand and Indonesia have also reported human cases of bird flu in the past few months.

"Fortunately, so far all the reported human patients were infected by sick poultry and where not acquired from human transmission," Dr. Omi said. It is crucial to detect the occurrence of human cases of bird flu.

"Each human case is very important," he said.

The WHO delegation including Henk Bekedam, WHO's representative in China, Lee Chin-Kei, project officer of WHO in China and Roy Wadia, Who's information officer in China congratulated Hunan for successfully treating the nine-year-old boy.

The WHO delegation met with local health officials in Hunan and called for the prompt and quick detection of human cases of bird flu and enhancement of the reporting of animal outbreaks.

(Xinhua News Agency December 23, 2005)