(Associated Press) -- Every hour a baby is born in China with syphilis, as the world's fastest-growing epidemic of the disease is fueled by men with new money from the nation's booming economy, researchers say.

The easy-to-cure bacterial infection, which was nearly wiped out in China five decades ago, is now the most commonly reported sexually transmitted disease in its largest city, Shanghai.

Prostitutes along with gay and bisexual men, many of whom are married with families, are driving the epidemic, according to a commentary published Thursday in the New England Journal of Medicine.

The increase reflects the country's staggering economic growth, providing both businessmen and migrant laborers more cash and opportunity to pay for unsafe sex while away from home.

"In the '50s and '60s in China, syphilis and other STDs were extremely uncommon. The number of new cases has just rapidly accelerated," Dr. Joseph Tucker, lead author and an infectious disease specialist at the University of North Carolina at Chapel Hill, said in an interview. "Even one baby born with syphilis in China is unacceptable."

Unlike other sexually spread diseases, such as gonorrhea or chlamydia, syphilis can eventually ravage the mind and kill if left untreated. A shot of penicillin is a cheap cure, but many people never experience specific symptoms and the disease remains undiagnosed.

With no mandatory routine screening in place for pregnant women in China, the rate of mother-to-child transmission jumped from 7 to 57 cases per 100,000 live births between 2003 and 2008, Tucker said.

In the U.S., despite laws in most U.S. states requiring testing during pregnancy, the disease is also making a comeback after nearly being eliminated 10 years ago. The Centers for Disease Control and Prevention reported last month that after a 14-year decline, the number of babies born with syphilis rose from 8 to 10 cases per 100,000 live births from 2005 to 2008, mostly among black women in the South. The country's overall syphilis rate rose 17 percent in 2008 from the year before, with more than 60 percent of cases linked to gay sex.

The World Health Organization estimates 12 million people are infected with syphilis worldwide each year, affecting some 2 million pregnancies, with about one quarter of them resulting in miscarriages or stillbirths.

Another quarter of the babies who survive are born underweight or with serious infections, upping a newborn's risk of death during the first fragile weeks of life. Syphilis can also cause deafness, neurological problems or bone deformities in newborns.

"This damage is irreversible," said Dr. Connie Osborne, a senior HIV adviser at WHO in China. "Prevention of maternal syphilis combined with routine screening of pregnant women and early treatment of neonatal syphilis can prevent most, if not all, cases."

In recent years, China's Communist government has made huge strides in openly addressing the spread of HIV, which is easier to transmit and catch if other infections exist. But social stigma remains a huge barrier for people infected with any sexually transmitted disease, making it important for tests and treatment to be moved out of doctors' offices and into brothels, clubs and communities where high-risk groups gather.

Paul Causey, a consultant with the Asia Pacific Coalition on Male Sexual Health in Bangkok, said reaching married men who have sex with men in China is particularly tricky because they remain deeply closeted and do not hang out with gay men socially. A lack of a thriving civil society to provide awareness and advocacy in China also creates challenges, often leaving the responsibility to local organizations and officials.

Syphilis was nearly eradicated in China in the 1960s after a propaganda blitz to shut down brothels which included mass screening and treatment of prostitutes. But as free-market reforms thrust the nation's economy into high gear in the 1980s, the disease rebounded at an unprecedented rate.

While other countries have higher syphilis rates than China, including many in Africa, cases are now rising by 30 percent every year in the world's most populous country, with the official government number tripling between 2004 and 2008 to nearly 280,000. Some of that may be linked to better reporting and screening, and one reason why the rate of syphilis among newborns may be growing faster is because they are being tested more than in the past, Tucker said.

China's government needs to better integrate screening for HIV and other sexually transmitted infections, as well as determine how and when testing and treatment should be carried out all the way down to the community level, Xiang-Sheng Chen, deputy director of China's National Center for Sexually Transmitted Disease Control said in a journal published by WHO last fall.

"Unlike many Western countries, China does not have an STI public health program - which it should have," said Chen, who co-authored the commentary. "State policy has focused mainly on HIV/AIDS."

Copyright 2010 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.