The number of spouses infected with HIV by their partners is increasing on the Chinese mainland, and most of those infected by spouses are females, a new report has revealed.

"The report will help devise better intervention methods to curb rising HIV transmissions within married couples and significantly reduce new infections," said Liu Kangmai, deputy director of the National Center for AIDS/STD Preve"ntion and Control (NCAIDS).

Released on Friday, the report by NCAIDS, UN Women and UNAIDS was based on a 2011 study conducted in six cities and counties in Yunnan, Henan, Sichuan, Guangxi and Chongqing. It surveyed more than 770 couples where one party was HIV positive.

According to estimates published by the Ministry of Health in 2009, about 15 percent of the estimated 740,000 HIV/AIDS sufferers on the Chinese mainland were infected by their spouses.

Of the 48,000 newly detected sufferers in 2011, at least 25 percent of the cases involving heterosexual sex were transmitted by spouses.

In the survey areas, the proportion of sufferers infected by spouses quadrupled between 2004 and 2011, the report said.

The most dramatic increase was in Sichuan province, where the proportion of sufferers infected by spouses jumped from 0.78 percent to 10.9 percent during that time.

The proportion was highest in Henan, where 20 percent of infections in 2011 were from spouses. In Yunnan, the number of wives infected by husbands was 6.6 times that of husbands who contracted the virus from wives, it showed.

Women currently account for nearly 30 percent of HIV/AIDS sufferers on the mainland, official statistics show.

Among them — most between 19 and 44 years old — 62 percent were married, while only 16 percent had never married.

He Tiantian, who heads the Women's Network Against AIDS, a civil society supporting females living with HIV/AIDS, was infected with HIV by her husband.

"Men are more likely to get infected by means of commercial sex and drug use. Women are, however, too weak to protect themselves sometimes, particularly in marriage," she said. Her claim was echoed by the finding in the report that women had less power in sexual relationships.

In remote areas of Sichuan, nearly 94 percent of the healthy wives were forced by infected husbands to have sex, both with condoms and without, said the report.

In addition, the policy of how and when to inform others about HIV infection also left married women exposed to secondary infections, said Wang Linhong, a women's and children's health researcher at the Chinese Center for Disease Control and Prevention.

According to Lu Fan, director of the policy research and information division of NCAIDS, only Henan, Yunnan, Zhejiang and Gansu have regulations requiring sufferers to inform their spouses of their HIV status within one month of diagnosis.

"Otherwise, local medical workers would do that. Such a policy better protects healthy wives," he said, adding that female sufferers were more likely to tell spouses about their diagnoses.

Unfortunately, in other parts of the country, it's mainly up to sufferers themselves to inform spouses, he said.

"Even in places with such a policy, it has been poorly implemented as one doesn't get fined or punished for hiding the truth from spouses," Wang noted.

"We should enforce HIV/AIDS education in local areas and strengthen the advisory service of medical staff to ensure spouses of HIV patients are informed in time to prevent more from becoming victims," Wang urged.

Zheng Xin contributed to this story.