Chinese leaders, including President Hu Jintao and Premier Wen Jiabao, on Monday called for enhanced vigilance and strict steps against the A/H1N1 influenza after the country's mainland reported its first case.

"We must attach great importance to the fact that the flu epidemic is still spreading in some countries and regions, and that China has discovered one case," Hu said after learning about the latest development of the epidemic.

He ordered governments at all levels to spare no efforts to put all emergency response measures in place in order to curb further spread of the disease.

A Chinese mainland male surnamed Bao, who recently returned from the United States, tested positive for the A/H1N1 influenza early on Monday, becoming the first such case reported on the Chinese mainland.

Chinese Vice Premier Li Keqiang visited the flu patient, medical staff and people under medical observation Monday in Chengdu, capital of southwestern Sichuan Province.

Chinese Vice Premier Li Keqiang (2nd L) communicates with the confirmed A/H1N1 patient through video at the Chengdu Infectious Disease Hospital, which accepted Chinese mainland's first confirmed A/H1N1 patient surnamed Bao, in Chengdu, capital of southwest China's Sichuan Province, on May 11, 2009.[Xinhua]

Li conveyed the concerns and greetings of President Hu and Premier Wen to them, listened to reports on flu prevention and control by the local health authorities and inspected the treatment, prevention and control work.

He called for enhanced prevention and control of the A/H1N1 influenza "in a spirit of taking responsibility for the mass's health" so as to ensure public health and safety.

The 30-year-old patient was at the Chengdu Infectious Disease Hospital. Those who had close contact with him were isolated for observation.

The patient is currently in a stable condition with a normal body temperature, and is "recovering", the health ministry said.

Li came to the Chengdu Infectious Disease Hospital and saw the patient who lived in a negative pressure isolation room via video.

He asked doctors about Bao's condition and treatment in detail and told medical staff to treat the patient scientifically in line with a preset plan so that he could recover soon.

Li asked medical staff to enhance self-protection and prevent hospital infection and the spread of the disease.

Some medical staff of the Sichuan People's Hospital where Bao went to after getting off the plane, were under medical observation in a hotel as these doctors and nurses had close contact with Bao during his stay in the hospital. Li came to the hospital to see them.

Holding a phone, he had a conversation with the medical staff under observation, asking them about their health and expressing his concern for them.

Li extended his gratitude to them for their "contribution to the flu prevention and control work as "they promptly discovered the flu case." He encouraged them to "maintain an optimistic attitude" and cooperate to complete the quarantine so as to return to work as early as possible.

Some medical staff under isolation said the quarantine measures were "quite necessary" and were "conducive to protecting their and all the people's health."

Visiting the Sichuan Center for Disease Control and Prevention (CDC), Li said this first mainland case of the A/H1N1 influenza had been confirmed "in a very short period of time" after "instant diagnosis and consultation."

He told staff to follow the case, promptly analyze the development of the disease, sum up experience and improve emergent measures so as to offer scientific backup to the flu's prevention and control.

Li said after the A/H1N1 flu was found in some countries, the central government took emergency measures to ensure stability.