The survey found 73.3 percent of youth in western China know how the HIV virus is spread and what they can do to protect themselves. That is about 20 percent points lower than youth in the rest of the country.

Many young people in the west know the HIV virus can be contracted through unprotected sex and blood transmission, according to the survey, which was published by China's Juvenile Research Center and the National Research Center for Science and Technology for Development.

However, more than 20 percent wrongly believe they can catch the disease by sharing a room with someone who has AIDS.

"The misunderstanding proves that they have exaggerated the possibility of AIDS infection," said Deng Xiquan, a doctor with the Juvenile Research Center.

Western China covers 11 provinces and regions and is home to 364 million people, or slightly more than 28 percent of the country's population. The Ministry of Health said earlier that young people in the region are a key target of an awareness campaign on the prevention and control of HIV and AIDS, as they are a high-risk group.

The survey suggested less than 60 percent of adults understand how AIDS is spread.

An estimated 650,000 people in China are afflicted by HIV or AIDS.