La nuova epidemia di sifilide in Cina

Su Internazionale n. 678 di questa settimana a pagina 84 e’ tradotto un articolo tratto da The Economist sui recenti studi che confermano una grande epidemia di sifilide in Cina a causa anche della recente relativa maggiore tolleranza del governo cinese nei confronti del mercato del sesso. L’articolo in lingua originale e’ visibile cliccando su Continua

Syphilis is spreading fast in China. That raises wider concerns
The Economist, Jan 13th 2007

The Dutch called it the Spanish disease; Russians the Polish disease; Turks, the Christian disease and Tahitians, the British disease. But syphilis, a sexually transmitted disease (STD), seems more of a Chinese disease these days. In China the chance of catching it is now more than 28 times greater than it was in 1993. Syphilis cases are increasing in many countries but the extent of China’s rise, in relative and absolute terms, dwarfs figures from America, Canada and Europe. That is the conclusion of a study by Zhi-Qiang Chen and his colleagues at China’s National Centre for STD and Leprosy Control published in the latest issue of the Lancet, a medical journal. Both the broader implications of the increase, and its details, are troubling.

Syphilis statistics are of more than just medical importance, says Myron Cohen, another of the study’s authors. The numbers provide a surrogate for the spread of STDs in a whole population. Like HIV, syphilis detection rests on accurate blood tests, whereas other sexually transmitted diseases are diagnosed by analysing genital materials under a microscope. That makes samples easier to come by.

Syphilis infections are assigned categories according to how the corkscrew-shaped bacterium is picked up, and how long it has been resident. Babies with congenital infections caught them from mothers with secondary infections. Primary infections are usually painless because the bacteria numb the nerves around the ulcers they cause. Eventually the bacteria enter the blood, leading to the spotty red rash that is characteristic of secondary infections that sent many an apparently upright Victorian gentleman scurrying to a doctor. But only after years of a latent infection, during which the disease cannot be passed on, does it re-emerge to cause neurological decline and death.

Dr Chen’s data reveal that primary and secondary infections, which indicate the number of new infections, rose sharply in the late 1990s, but have remained roughly flat ever since. Congenital infections, on the other hand, have risen by an average of 72% a year since the early 1990s, and that rate seems to be accelerating. Together, the two trends suggest that many Chinese with the most risky sexual behaviour—prostitutes and their customers, and gay men—now have latent forms of the disease, and that women are more at risk of new sexual infections.

An explosion in infectious diseases is a common side effect for any rapidly growing trading centre where internal and international migration make for a burgeoning population. Quarantine (the “quarantina”) was invented in renaissance Venice after an outbreak of bubonic plague. A resurgence of STDs in China has accompanied the re-establishment and growth of the sex trade.

When the Communists came to power in 1949, China was suffering from one of the largest syphilis epidemics in history. One in 20 of the urban population, only slightly fewer of the rural population, and 84% of prostitutes were infected. Mao Zedong’s subsequent public-health efforts were effective but typically bullying. He all but eliminated syphilis and other STDs from China by writing off peasant debt, so women faced less pressure to turn to prostitution. He closed brothels and locked up sex workers in “re-education” camps. But less exposure to STD-causing pathogens then means that the modern Chinese population is unusually susceptible to infection now.

Nor does it help that China’s healthcare system has seen serious disruptions. Mao’s public-health system was dismantled virtually overnight in the early 1980s, without the introduction of alternative insurance schemes. It is improving slowly now, but there are few resources at hand. Estimates by the World Health Organisation suggest that the government spent just $22 on health, per person, in 2003, much less than the $96 in Brazil or $98 in Russia. When it comes to STDs, though, policies and spending only work when they are unimpeded by stigma. So it is encouraging that a national study of China has been published at all.