A 31-year-old man in south China's Guangdong Province has been confirmed to have contracted bird flu, bringing the country's total human infections of the disease to 19, the Chinese Ministry of Health said yesterday.

The patient, surnamed Jiang, is a migrant worker in Shenzhen City. He had fever and pneumonia on June 3 and has been hospitalized since.

He is listed in critical condition, the ministry said in a report.

Researchers found that before developing symptoms, Jiang had visited a local market several times where live poultry were sold.

Jiang's samples tested positive for H5N1 by the Shenzhen Center for Disease Control and Prevention and the provincial and national CDCs.

He has been confirmed to be infected with bird flu in accordance with the standards of the World Health Organization and the Chinese government, said the ministry.

The ministry has reported the new case to the WHO, China's Hong Kong, Macau and Taiwan regions, as well as several foreign countries.

Local health authorities on Tuesday said they suspected Jiang was infected with the bird flu virus. All 98 people who had close contact with Jiang tested negative for the disease, the local health bureau said yesterday.

The health department of neighboring Hong Kong on Tuesday warned the public to be vigilant against bird flu, while Macau health authorities announced on Wednesday it would halt the import of live poultry from Shenzhen.

Jiang is the 19th human case of bird flu reported in China. Of the previous 18 cases, 12 have died.

Globally, 225 human infections, including 128 deaths, have been recorded by the WHO.

Health experts fear the bird flu virus would mutate into a form that can easily pass between people, causing a global pandemic.

The Chinese government is "keeping a close eye on bird flu and have strengthened scientific research and nationwide surveillance," Ministry of Health spokesman Mao Qun'an said on Monday.

One day later, a Shanghai-based company was approved by the State Food and Drug Administration to produce a generic form of the anti-flu drug Tamiflu.

Tests showed the domestic drug was as effective and safe on humans as the imported version, the SFDA said.

Tamiflu is an anti-viral drug considered the most effective treatment available to counter the H5N1 strain of bird flu.

On Wednesday, the Ministry of Agriculture said China has developed three kinds of new bird flu vaccines for use in birds.