Massive increase in incidence of syphilis in China

The number of reported cases of syphilis in China increased massively from just 194 in 1985 to over 113,000 in 2005, according to an article published in the January 13th edition of The Lancet. What’s more, the study’s investigators believe that improved surveillance would show an even higher increase. A national campaign for the detection, treatment, and prevention of syphilis is, the investigators add, urgently required.

Syphilis was first diagnosed in China in the early years of the 16th century and by 1949 the country was experiencing one of the worst syphilis epidemics in history. Surveillance data from the early 1950s suggest that the infection was present in 82% of prostitutes, 5% of the general population in some large cities and 1-2% of the rural population.

Healthcare was a priority of the communist government of Chairman Mao, and the control of sexually transmitted infections was a key aim. Mass sexual health screening programmes were introduced, free treatment for infections was provided, and brothels were closed. By the 1960s, studies by both Chinese and international investigators suggested that sexually transmitted infections had been virtually eradicated from China.

However, by 1979, syphilis had reappeared in the country, and the rapid social and economic changes which China is experiencing appear to be providing an ideal environment for the rapid re-emergence of a syphilis epidemic.

Using data obtained from the Chinese Centre for STD Control and surveillance data from 26 ‘sentinel sites’, a team of Chinese and US investigators set out to determine the growth and magnitude of the re-emerging syphilis epidemic in China.

Their research revealed that there has been an explosion in the amount of syphilis at all disease stages as well as congenital syphilis in the 20 years since 1985.

Between 1989 and 1993, surveillance data showed that the incidence of syphilis was just below 0.2 cases per 1000,000 people. It then increased sharply to 6.5 cases per 100,000 in 1999 before falling back slightly (a decline attributed by the investigators to administrative changes). By 2005, syphilis incidence was 5.67 cases per 1000,000 people, with primary and secondary syphilis having an incidence of 5.13 cases per 100,000 people.

A marked increase in the incidence of congenital syphilis was also recorded by the investigators. In 1991, the incidence of congenital syphilis was 0.01 cases per 100,000 live-births, but by 2005 this had increased to 19.68 cases per 100,000 live births.

Syphilis predominantly affected younger individuals, with more than 70% of cases in the last decade diagnosed in the 20 – 49 age group.

Syphilis was reported in every one of China’s 2,882 counties, with Shanghai having the highest rate at 55.31 cases per 100,000 people.

Data from sentinel sites showed an even higher incidence of the infection. In 1993, these 26 sites had an incidence of 32.9 cases per 100,000 people, and by 2001 this had increased to 28.9 cases per 100,000 people. Despite only covering 3% of China’s population, the 26 sentinel sites reported 18% of total syphilis cases recorded in China between 1995 and 2001.

“Surveillance data and focused reports provide compelling evidence of a substantial and worsening epidemic in high risk populations and in the general population”, write the investigators. After reviewing previously published research they estimated that just under 0.5% of pregnant women in China are infected with syphilis, as are 1% of sex workers, 12% of incarcerated sex workers, 7% of drug users and 15% of men who have sex with men.

The increasing privatisation of healthcare in China could, the investigators suggest, be contributing to the worsening syphilis problem. They highlight research showing that 80% of women with symptoms of a sexually transmitted infection in Beijing did not seek medical treatment either because they could not afford to do so, or because they did not recognise the symptoms of a sexually transmitted infection.

Biological factors could also be facilitating the spread of syphilis. The investigators suggest that the virtual eradication of the infection in the 1960s and early 1970s lead to a loss of ‘herd immunity’ to syphilis, meaning that the current generation of sexually active young adults is “completely susceptible to this infection.”

Social forces are also contributing to the rapid reemergence of the infection, with a large number of migrant men “creating an increased demand for sex work.”

A key component of any efforts to control syphilis must, the investigators write, be the introduction of free screening and treatment programmes. They highlight the success of such initiatives in Mao’s China in the 1950s and 1960s. The investigators also say that China needs to develop sexual health education programmes.

“China has shown once before that the control of syphilis is possible”, conclude the investigators, “and we expect that a new national campaign, although challenging, will show benefit.”

The author of an accompanying editorial stresses that Chinese public health facilities must take the lead in fighting syphilis, but that syphilis control measures must respect individual rights and freedoms. He writes, “China and other countries must accept that disease control is an issue of public good that cannot be achieved through market forces alone. Investment in infrastructure for public health that respects individual rights and freedoms will give China and other countries the seatbelt necessary for safe travel on the global economic superhighway.”