Like millions of other ordinary rural folk in China, the farmer never dreamed that he could marry a foreign woman.Neither did he know the risk.

"I have been living with HIV for several years," said the 52-year-old in Pingxiang, a border city of southern China's Guangxi Zhuang autonomous region adjacent to Vietnam.

The HIV sufferer is too afraid to use his real name, instead he uses the pseudonym Huang Haitong. He was born in the central province of Hunan. Huang went to Guangxi in 1998, and there he opened a small hotel. His wife, from Vietnam, was once a sex worker.

"She had a husband," Huang recalls in a heavy Hunan accent. After Nguyen Thi Hoa, also not her real name, gave birth to a boy, her husband died.

Cross-border marriage is commonplace in Guangxi. Huang married Nguyen in 2004. Two years later, she suffered recurring herpes outbreaks on her face. The couple spent a lot of money but the outbreaks didn't stop. Finally a doctor suggested they take a HIV test.

When telling the story, Huang's voice was low and calm. But he said on hearing the news, he felt his world had collapsed.

"I had never sold blood, nor was I addicted to drugs." He suspected that he got the virus from his wife, but added that it was not important now to find out which one of them had infected the other.

In many parts of China, HIV/AIDS still has a huge stigma. Knowing their condition, Huang's landlord asked the couple to leave. Over a three year period, they moved four or five times and Huang had to close his hotel.

Nguyen gave birth to a girl in 2009. Now the family of four lives in a 30-square-meter rented apartment in the downtown area of Pingxiang, sleeping in one bed. They have an electrical fan to cool them during torridly hot summer days, but they have no television.

Huang is not a local so he can't get a low-income subsidy from the government. Nguyen, working as waitress in a hotel, supports the family with her 900 yuan a month.

CROSS-BORDER HIV TRANSMISSIONS

Covering 650 square km, Pingxiang, with its population totaling 110,000, is dubbed the "southern gate of China" and known as an important place of trade on the China-Vietnam border.

It is also seriously affected by HIV/AIDS.

Guangxi, with 50 million people and more than 60,000 HIV infections by the end of last year, was ranked the second among all autonomous regions, municipalities and provinces. Pingxiang had 638 people who were HIV positive in September.

Sex has become the top transmission channel in recent years, said He Bo, director of local disease control and prevention center (CDC) in Pingxiang. He noted that among the newly infected people in 2011, three-fourths were heterosexuals.

Cross-border transmission is common in Pingxiang.

According to a report on the official website of UNAIDS, Vietnam, with its population of 84 million, estimated 293,000 people living with HIV in 2007. "Of all reported HIV cases, 78.9 percent are 20-39 years old," according to the report. The border areas especially saw high infection rates.

Vietnamese sex workers are generally more likely to carry HIV than Chinese sex workers, He said. "Among every 100 Vietnamese sex workers two or three are infected, whereas the infection rate of Chinese sex workers is around one percent."

Some Vietnamese sex workers married Chinese, Zhong Haidong, a staff member of the CDC, said.