BEIJING, Dec. 2 (Xinhuanet) -- Like millions of other people living in China's countryside, Huang Haitong in the Guangxi Zhuang autonomous region never dreamed that he could marry a foreign woman.
Neither did he know the risk of doing so.
"I have been living with HIV for several years," said the 52-year-old resident of Pingxiang, a city across the border from Vietnam.
The man requested anonymity, saying he would rather be known by his pseudonym.
He was born in Hunan province and went to Guangxi in 1998, opening a small hotel there. His wife, who had come from Vietnam, had once been a sex worker.
His wife, whom he preferred be known by the pseudonym Nguyen Thi Hoa, once had another husband but he died after she gave birth to her son.
Cross-border marriages are common in Guangxi. Huang married Nguyen in 2004. Two years later, she began suffering from recurring outbreaks of herpes on her face. The couple spent a lot of money to try to treat the condition, all to no avail. A doctor eventually suggested they take a HIV test.
Telling the story, Huang remained composed. His reaction was quite different when he first learned of his infection.
He said he felt as if his world had collapsed.
"I had never sold blood and I wasn't addicted to drugs," he said.
He suspected that he had got the virus from his wife. At the same time, he thought there was little point in trying to ascertain who had infected whom.
In many parts of China, carrying HIV or AIDS is still looked upon as a mark of disgrace. Learning that Huang and his wife had been infected, his landlord asked them to leave the place they had been renting. During the next three years, they moved as many as five times and Huang had to close his hotel.
Nguyen gave birth to a girl in 2009. The family of four now lives in a 30-square-meter apartment in downtown Pingxiang.
They sleep in a single bed, are cooled on hot days by an electric fan and make do without a television.
Huang is not a native of the city so he cannot obtain subsidies from the local government.
Nguyen supports the family on the 900 yuan (140 US dollars) she makes each month working as a waitress in a hotel.
Pingxiang, which occupies 650 square km and has a population of 110,000, is known as an important place of trade on the border between China and Vietnam.
It has also seen serious consequences from the spread of HIV and AIDS.
Guangxi contained 50 million people and 60,000 HIV infections by the end of 2010. Pingxiang itself was home to 638 people who were HIV positive in September.
In recent years, the virus has been transmitted most often through sex, said He Bo, director of Pingxiang's disease control and prevention center.
Among those who were infected this year, three quarters were heterosexuals.
Many times, the virus comes in from across the border, he said, adding that Vietnamese sex workers are generally more likely to carry HIV than Chinese sex workers.
"Among every 100 Vietnamese sex workers, two or three are infected, whereas the infection rate of Chinese sex workers is around 1 percent."
Counting the number of cross-border marriages that exist is difficult, largely because such unions are often complex and are therefore not recorded by civil affairs.
To curb the sexual transmission of HIV across the border, the Pingxiang center for disease control and prevention started a campaign to protect the health of Vietnamese sex workers.
He Bo, the director, said Pingxiang has worked with Lang Son, a city in northern Vietnam, toward that end.
Sex workers now receive regular health checks. Two workers with the local center for disease control and prevention also teach sex workers how to protect themselves against HIV.
One of them is Hoang Thu Mai, a Vietnamese woman. The other is Li Bing, who majored in the Vietnamese language at college.
"Each week I spend two days visiting Vietnamese sex workers, teaching them basic things about HIV and AIDS," Li said.
"It's hard to gain their trust," she said. "If I preach all the time and ask them to use condoms, they get bored."