Syphilis, which was largely eliminated in China between 1960 and 1980, has returned with a vengeance and urgent intervention is needed to curb the epidemic, according to researchers in China and the United States.

A study published in The Lancet found that the total incidence of syphilis in China increased to 6.5 cases per 100,000 people in 1999 from less than 0.2 cases per 100,000 in 1993.

“Syphilis has returned to China with a vengeance. The data demonstrates a syphilis epidemic of such scope and magnitude that it will require terrific effort to intervene,” said lead researcher Dr. Myron S. Cohen, director of the Center for Infectious Diseases at the University of North Carolina at Chapel Hill School of Medicine.

When the communist party took power in 1949, China was suffering one of the biggest syphilis epidemics in human history and the government launched a prolonged campaign to eliminate sexually transmitted diseases.

The study linked the re-emergence of syphilis to economic reforms and globalization in China.

“These changes have led to income gaps and a cultural climate that favors re-emergence of prostitution due to a substantial majority of men and a large migrant population of male workers,” the report said.

“Changing social practices such as people experimenting with sex at earlier ages and before marriage, as well as increasing costs of individual health care, also contribute.”

Of the three categories of disease - primary, secondary and tertiary - the first two represented 5.7 cases per 100,000 people in 2005. This latter incidence is substantially higher than in most developed countries, including the U.S., which reported 2.7 cases per 100,000 of primary and secondary syphilis in 2004.

The researchers based their report on data collected from China’s national sexually transmitted disease (STD) surveillance system and sentinel site network.

Also alarming is the rate of congenital syphilis, Cohen said, which increased to 19.68 cases per 100,000 live births in 2005 from 0.01 cases in 1991 - an average yearly rise of 71.9 percent.

Congenital syphilis occurs when a pregnant woman with syphilis passes the infection to her baby in the womb. Many cases result in miscarriage or stillbirth, and surviving babies may have serious problems with the brain, liver, and other organs.

By 1964, syphilis had become rare and was virtually absent for the next 20 years.

However, that means the general population of young, sexually active individuals has no natural immunity to the disease.

“Sexually active individuals would be completely susceptible to this infection,” the report said, noting that syphilis increases the risk of both transmitting and getting infected with HIV, the virus that causes AIDS.

Syphilis can be treated with antibiotics. Left untreated, it can cause serious damage to the nervous system, heart or brain, and can be fatal.