Almost two-thirds of all new syphilis infections in the United States involved gay or bisexual men, according to US government figures released on November 8th. The annual sexual health surveillance data also showed that even though new cases of gonorrhoea have fallen to an all-time low in the US, a quarter of cases of the infection of gay men involved a strain of gonorrhoea which was resistant to the recommended, first-line oral antibiotic treatment.
“Gay and bisexual men should be concerned about the threat of STDs”, said a spokesperson for the US Centers for Disease Control and Surveillance which compiled the figures.
In total, 7,177 cases of primary or secondary syphilis were recorded in 2004, an 8% increase on the year before. Most of these new infections were amongst men, and since 2000, 81% of all new syphilis infections have involved men.
The increase in new cases of syphilis is particularly marked in gay and bisexual men. In 2000, only 5% of syphilis cases were in gay men, however in 2004 this had leapt to 64%.
For the first time in ten years, the number of new syphilis cases in African Americans also increased in 2004, the number of new infections increasing by 16% on the year before.
Recent increases in syphilis amongst gay men in the US have also been seen in other industrialised countries. Starting in 1999, outbreaks of syphilis were seen amongst gay men in London, Manchester and other cities with a large gay population. Oral sex was thought to be the likely mode of transmission in a significant number of cases. Surveillance data from the United Kingdom and other countries also indicates that HIV-positive gay men have been disproportionately affected by the infection.
Although the total number of gonorrhoea cases fell in the US in 2004 by 2%, the CDC reports that there was an increase in the incidence of infections involving resistance to fluoroquinolone antibiotics (such as Cipro) from 4% in 2003 to 7% in 2004.
Resistance to fluoroquinolines was eight times higher amongst gay men with gonorrhoea than heterosexuals (24% versus 3%). US guidelines for the treatment of gonorrhoea were recently changed because of the high incidence of antibiotic resistance. It is now recommended that gay men are no longer treated with drugs from the fluoroquinoline class. Nor is this class of antibiotics recommended for the treatment of any gonorrhoea in California or Hawaii.
UK treatment guidelines for gonorrhoea were changed in 2003 when it was found that 10% of all new cases of the infection were resistant to Cipro and similar drugs.
“STDs increase the risk of HIV transmission by up to five times,” said a spokesperson for the CDC. “The rise in STDs could indicate the potential increases in new HIV infections among gay men”, they warn.
However, increases in the rates of sexually transmitted infections do not necessarily mean that the number of new HIV infections will increase. Sexual activities, such as unprotected oral sex, which involve a significant risk of transmission of a bacterial infection, do not involve a high risk of HIV transmission. A study conducted in Los Angeles and San Francisco showed that even though the number of new syphilis cases increased massively between 1999 and 2002, the number of new HIV infections remained stable.