BE VIGILANT: Vice Premier Li Keqiang (second from left) talks with a confirmed A/H1N1 flu patient through video at the Chengdu Infectious Disease Hospital, in Sichuan Province, on May 11 (XINHUA)

Chinese President Hu Jintao and Premier Wen Jiabao called on citizens to be vigilant and take strict countermeasures against the A/H1N1 flu after the country confirmed its first mainland case on May 11.

The victim, a 30-year-old man surnamed Bao, is a student at a U.S. university. He had returned to the Sichuan provincial capital of Chengdu on a Northwest Airlines flight from St. Louis, Missouri, via Tokyo and Beijing.

Bao was suffering from a fever, sore throat, coughing, a stuffy nose and sneezing during the flight from Beijing to Chengdu. He went to Sichuan People's Hospital after getting off the plane, and tested "weakly positive" twice for the A/H1N1 virus strain by the Sichuan Center for Disease Control and Prevention.

The Chinese Ministry of Health (MOH) sent a team of specialists to Chengdu, where local health authorities were told to send a virus sample to the Chinese Center for Disease Control and Prevention (CDC) for a second check.

Bao was then transferred to the Chengdu Infectious Disease Hospital. Authorities also quarantined his girlfriend, father and a local taxi driver, according to reports by Xinhua News Agency. The case was reported to the World Health Organization and other countries.

A second case of A/H1N1 flu was reported and confirmed on May 12 in Jinan, east China's Shandong Province, according to the MOH. The case involved a 19-year-old man surnamed Lu who studied at a Canadian university and traveled from Canada to arrive in Beijing on Flight AC029 on May 8.

The Jinan city and Shandong provincial centers for disease control and prevention conducted tests on the virus specimen of the patient respectively, which showed that he was "suspected positive" for the A/H1N1 virus. The specimen was sent to the CDC for further testing and led to a confirmation.

The person was isolated and received treatment in Jinan, and was already in remission, the MOH said.

The State Council held a meeting on May 11 to discuss further steps to take for the prevention of the disease. It was agreed at the meeting that China faces a "complicated and grave" situation as the epidemic has not yet been controlled globally and new cases keep emerging.

Strict quarantines continued to be adopted for people, goods and vehicles entering China from countries that have reported A/H1N1 cases.