Despite highly cautious countermeasures, the number of A/H1N1 flu cases in China may rise dramatically in the future, said a leading expert.

Once the virus enters a country, it begins to spread internally, said Scott Dowell, director of the Global Disease Detection Program at the US Center for Disease Control and Prevention in Atlanta.

"We anticipate there will be domestic transmission of the virus in China like in other countries including Canada, Panama and Japan," he said.

In most of the countries hit by the H1N1 flu, the cases have generally been found in international travelers instead of people within the countries, he told China Daily.

For China, however, that could soon change.

"I agree with Dowell. The virus has its natural path of evolution," said Feng Zijian, director of the emergency response department of the China Center of Disease Control and Prevention.

"However, the government and the Chinese people are doing their best to avert a possible outbreak," Feng said yesterday.

China has beefed up efforts to combat the flu as it spreads worldwide. Although quarantines involving Chinese and foreigners have been controversial, the Chinese government insisted the quarantines were legal and useful, Xinhua reported.

China's Ministry of Health has urged all overseas students to pay attention to their health before they come back.

An online survey of 15,002 people by the China Youth Daily Social Survey Center released on Tuesday showed more than 85 percent of those polled are satisfied with government measures to contain the virus.

If China can slow the predicted spread of H1N1, it may buy time for vaccine production, according to Dowell.

"The hope would be that there's not a very large outbreak in China in the next couple of weeks. That would give everybody there a few months to plan," he explained.

Yin Hongzhang, director of the biology production department of China's State Food and Drug Administration, said on Tuesday that China is likely to receive flu strain samples by early June that will enable it to manufacture an H1N1 flu vaccine by July.

As of yesterday, the Chinese mainland had 13 confirmed H1N1 flu cases with the latest being reported yesterday in Jiangmen City in Guangdong province.

The latest patient, a 62-year-old ethnic Chinese man of US nationality, arrived in Hong Kong on May 17 on Cathay Pacific flight CX 879 from San Francisco.

He then took a shuttle bus to Baisha Town of Jiangmen on May 18.

He developed a fever on May 20. On May 23, he tested positive for H1N1 flu, which was confirmed early yesterday.

Twenty-three people who had close contact with the man are in quarantine.

So far, all the confirmed flu cases have been diagnosed among those returning from abroad, mostly from North America.

For that, Dowell admitted "it's been a little bit of a new experience for the US being a [virus] exporting country."

In mid May, University of Hong Kong microbiologist Ho Pak-Leung said the US should stop passengers with a fever from boarding flights.

Hong Kong has called on the US to screen outgoing air passengers to avoid exporting the virus, the South China Morning Post reported on May 14.

Wang Zhuoqiong and Li Wenfang contributed to the story

(China Daily May 28, 2009)