Three virus strains of A/H1N1 influenza donated by the United States will be delivered to China in the upcoming two to three days for medical analysis, Chinese disease control official said on Friday.

"The strains, one segregated from a Mexican patient and two from U.S. patients, are on their way to China," said Qiang Zhengfu, chief of the international cooperation section with Chinese Center for Disease Control and Prevention (CDC), in an interview with Xinhua.

Another virus strain donated by China's Hong Kong Special Administration Region will be delivered to the Chinese mainland 'soon', Qiang said.

Chinese medical experts will conduct analysis on the strains to find out the cause of the A/H1N1 influenza and the virus's pathogenic ability, but more importantly, the research will greatly improve the accuracy and speed of a test reagent applied to diagnose suspected cases of the disease.

The research on the real A/H1N1 influenza strain will also help improve surveillance of the disease's epidemic situation, the official added.

Chinese Health Minister Chen Zhu announced on April 30 that the country's disease control experts and scientists had developed an effective test reagent for instant diagnosis of the virus's infection.

Since the influenza's outbreak was announced by the World Health Organization (WHO) last month, 894 confirmed cases have been reported in the United States by 9 p.m. Friday, and a 25-year-old Mexican patient was found and quarantined in Hong Kong.

The CDC has invited to WHO and U.S. disease control experts to discussions with Chinese experts on how to control the spread of the epidemic.

Qiang said the American experience gained in the outbreak proved that the A/H1N1 influenza could be discovered by regular monitoring and surveillance.

Many international disease control experts believed that as China had not recorded a case so far, it is left with more time to prepare for a possible new wave of outbreak in the coming autumn and winter.

Dong Xiaoping, an epidemic scientist with the CDC, told Xinhua that according to a record of the flu's infection development provided by the Americans, the virus seemed to be weaker than earlier pandemics.

"We can't say the virus's transmission capacity is declining based on the information at hand," Dong said, "but the capacity is limited."

Although the strains donated by the United States and Hong Kong were believed to be helpful, Chinese drug watchdog said also on Friday that they could not be used to produce human vaccines against the A/H1N1 influenza.