China is to launch a nationwide survey of people who sold their blood in the 1990s as it tries to track down HIV/AIDS victims, state television said on Wednesday.

China passed a law in August banning the buying or selling blood to prevent the spread of AIDS after botched selling schemes of the 1990s.

“At present, the AIDS epidemic situation in our country is severe,” ministry of health spokesman Mao Qunan was quoted as saying. “Infections and death are booming from people who were infected with AIDS by selling blood before and after 1995.”

A pool of people infected with the HIV virus that can lead to AIDS had yet to be traced after the 1990s blood-sale scandal in the central province of Henan. Rural poor repeatedly sold plasma at blood collecting stations, where blood was pooled and plasma extracted before blood was returned to donors so as to avoid anemia.

One infected donor would infect the entire pool of donors. In some of the worst affected Henan villages, over 20 percent of the people were infected, said the Global Fund to Fight Aids, Tuberculosis and Malaria.

The China survey aimed to get a clear picture of the extent of the epidemic in the country, Mao was quoted as saying.

China, which was slow in acknowledging the AIDS epidemic, says it has 840,000 HIV/AIDS cases, but experts say the figure is more likely to be between one million and 1.5 million.

The United Nations says the number could rise to 10 million if the epidemic is not treated seriously.