Research published in the Lancet indicated there are now about six cases for every 100,000 people in China.

"The bacterial infection reemerged in the 1980s as the economic boom increased migration to cities by rural workers," explained Chen Xiangsheng, deputy director of China's National Center for STD Control, in a recent World Health Organization bulletin. "Migrant workers, mainly young men who have left their wives back in their hometowns, make up much of the clientele of low-tier sex workers.

"It's difficult to promote condom use among these prostitutes because they are poorly educated and some cannot even afford a condom," added Chen, who co-authored the paper on syphilis published in the New England Journal of Medicine.

Infection rates have also soared among farmers and retired people, according to a 2006 report on syphilis and gonorrhea by the STD center of the Chinese Center for Disease Control and Prevention.

"Even if they know they have caught syphilis or another STD, these three groups are often too ashamed to see a doctor because of the stigma, and will most likely pass the virus to their spouses," said professor Gong Xiangdong at the STD center.

Chinese people are still deeply conservative when it comes to discussing sexual health, and discrimination against those diagnosed with STDs, as well as many other conditions, remains a real problem.

Because of this reason, studies that suggest more than half of China's syphilis sufferers do not seek the medical treatment they need.

Prevention plan

Although the explosion in cases of syphilis has already drawn attention from the central government and health experts, critics argue that work to curb the epidemic are falling far short of the mark.

"China has made great progress in preventing the spread of HIV and AIDS in recent years," said Wan at the Sichuan Institute of Dermatology and STD Prevention. "But even though monitoring and controlling syphilis is not technically difficult, the government is still failing to do enough."

He has called for authorities to introduce a systematic program for syphilis testing and control for high-risk groups as soon as possible.

Free screening is already offered in major cities like Shenzhen, an industrial hub in Guangdong province, but experts say such services should be rolled out in rural areas, especially counties with large concentrations of ethnic groups.

Studies show people with syphilis have an increased risk of acquiring and transmitting the deadly HIV virus, "so why not make full use of existing facilities (to curb the spread of HIV) to publicize, test and treat syphilis at the same time?" added Wan.

According to the New England Journal of Medicine report, an ongoing project is already analyzing the impact of expanded STD care on the rate of HIV infections.

Meanwhile, government programs have laid the foundations for change by introducing syphilis testing at non-traditional sites, as well as allowing the development of advocacy organizations and support groups.

China's disease control officials are also finalizing a nationwide syphilis prevention and control plan, which will be aimed at drastically reducing the infection rate over the next five years.

"Broader recognition of STDs as a public health concern, renewed financial commitment by the government and technical support from advocacy organizations are imperative if syphilis is to be controlled once again," said Wan.

Ultimately, he said, the solution lies with individuals, who must ensure that they and their partners are healthy before they have sex.

"Being cautious about your own health is not only showing respect to yourself, but also shows respect to the people you are with," he added.