The Chinese mainland and Hong Kong yesterday confirmed their second cases of H1N1 flu, exposing shortcomings in the nation's monitoring system.

The Ministry of Health said yesterday a 19-year-old student surnamed Lu, confirmed to have the virus, was "recovering and his temperature is back to normal."

Lu left Beijing by train D41 on Monday evening for Jinan, capital of Shandong. He called the provincial Center for Disease Control and Prevention (CDC) while on the train.

He had arrived in Beijing from Canada last Friday. A spokesman for the Canadian embassy said yesterday that Lu boarded Air Canada flight AC029 in Toronto at noon on May 7 and stopped over in Vancouver.

Lu's girlfriend, a 17-year-old surnamed Zhang who traveled with him and later went home to Tianjin in a car, was also quarantined yesterday.

She has no symptoms of the virus, the Tianjin health department said yesterday.

The developments came two days after a 30-year-old man surnamed Bao was found to have contracted the virus after returning from the United States. He was also said to be recovering well in Chengdu, Sichuan province.

In Hong Kong, a 24-year-old resident was confirmed yesterday to have contracted the virus. The unidentified man took Cathay Pacific flight CX879 from San Francisco and arrived in Hong Kong at 7 pm on Monday with a sore throat, said Dr Thomas Tsang, controller at the city's Center for Health Protection.

The man, who checked into an airport clinic before being taken to hospital, was said to be in a stable condition.

The discovery comes nearly two weeks after Hong Kong confirmed its first patient, a 25-year-old Mexican whose entry in the city led authorities to lockdown a downtown hotel.

Fifty-one passengers sitting three rows in front of and behind the latest Hong Kong patient have been traced.

Six of them who were in Hong Kong were quarantined, while the remaining 45 had left the city.

The patient passed the infrared thermal screening at the airport because his fever was not high enough, Tsang explained. More such "imported" cases are expected, he said.

The Jinan Railway Bureau said it did not receive any notification from the local CDC about the latest case.

Of the 44 in the same carriage as Lu, 19 have been quarantined and did not show any flu symptoms yesterday.

The World Health Organization said yesterday that nearly 6,000 people in 33 countries have been infected by the H1N1 virus. In its latest tally, the WHO said the virus has killed at least 56 people in Mexico, three people in the United States, and one each in Canada and Costa Rica.