HO CHI MINH CITY, June 23 (Xinhua) -- Vietnam's Ho Chi Minh City has recently detected 12 human cases of H1N1 bird flu virus infection, local media reported Saturday.

After testing specimens from 24 suspected cases of H1N1 infection, Cho Ray Hospital in the city has found that 12 people have suffered from the bird flu, of which two have been discharged from the hospital and 10 are still under treatment, Vietnam News Agency reported.

Early this month, Tu Du Hospital in the city spotted 28 suspected and confirmed cases of H1N1 infection, including 16 confirmed ones.

Vietnam experienced an H1N1 pandemic in 2009, with over 9,000 cases of people contracting the disease and nearly 20 deaths within four months of the year, according to the Health Ministry.

In a tropical country like Vietnam, the bird flu circulates the entire year round, usually reaching several peaks in the rainy season. The H1N1 virus causes pernicious respiratory infection.