They said syphilis has been on the rise since the beginning of the 21st century in high-income countries, but because the disease had been well controlled in the 1990s, doctors may not be screening for it.
Syphilis infects some 12 million people worldwide every year. Most cases are acquired through sexual contact with a syphilis sore. Pregnant women can pass it on to their babies.
"The key message here is that syphilis is again on the rise in several developing countries. In many of these countries we are seeing very high rates in men who have sex with men," said Dr Kevin Fenton of the US Centres for Disease Control and Prevention, whose study appears in the journal Lancet Infectious Diseases.
Fenton said the resurgence demands new training efforts among health-care professionals. "In many countries, physicians may have lost some of the skill sets associated with diagnosing syphilis," Fenton said in a telephone interview.
The CDC last week said the US syphilis rate rose once again in 2007, marking the seventh consecutive year of increases. Homosexual and bisexual men accounted for 64 percent of syphilis cases in 2007, up from about 5 percent in 1999.
Rife among high-risk groups
The recent resurgence is among a sub-group of men who have sex with men and engage in high-risk sex with multiple partners.
If not addressed, Fenton said the disease could become far more widespread.
"We have seen with other epidemics of sexually transmitted diseases that even if the initial rise occurs in men who have sex with men, it is unlikely to stay in that group for any long periods of time," Fenton said.
"The data suggest we are now seeing increases among heterosexuals in the US and in Europe as well," he said.
With HIV/Aids in the forefront, people pay little heed to other sexually transmitted infections (STI), letting their guard down and exposing themselves to other very uncomfortable and even lethal STIs.
Like many other sexually transmitted diseases, syphilis raises the likelihood of infection by or transmission of the human immunodeficiency virus, which causes AIDS.
Syphilis is caused by the bacterium Treponema palladium. It starts out as a sore, but progresses to a rash, fever, and eventually can cause blindness, paralysis and dementia if left untreated.
Fenton and colleagues argue that the resurgence calls for swift public health intervention, including screening programs to prevent the spread of the infection, mass media campaigns, efforts to change behaviour in high-risk groups and distribution of condoms.
"Efforts must be made to incorporate and evaluate new diagnostics tools, social network approaches, innovative evidence-based prevention interventions, robust disease surveillance and systematic monitoring and evaluation of prevention, treatment and care activities," they wrote. – (Julie Steenhuysen/Reuters Health)
SOURCE: Lancet Infectious Diseases, April 2008.