Lymphograunuloma venereum (LGV) is a genital/anogenital bacterial infection caused by a particularly invasive strain of Chlamydia trachomatis.
It was considered relatively rare until 2003, when around 100 cases were reported in gay men in Rotterdam in the Netherlands, most of whom were also HIV positive or had other sexually transmitted infections, including hepatitis C.
Since then outbreaks have been reported in Antwerp, Belgium, Hamburg, Germany, and Paris, France. Cases have also been reported in Sweden, and most recently in several US cities, including New York, San Francisco, and Atlanta.
Last year, one of the UK's leading HIV charities, The Terrence Higgins Trust, and the Health Protection Agency, which monitors cases of the disease, took steps to alert clinicians and those most at risk to the spread of the infection.
In January 2005, the first 24 cases were reported in the UK, mostly from sexual health clinics in London. All were in gay men, 17 of whom were HIV positive. Four also had hepatitis C infection.
Five thought they had caught the infection in mainland Europe, while the others said they had become infected in the UK. By mid February, a total of 34 cases had been reported.
The infection usually manifests as an ulcer or papule, and symptoms usually include rectal inflammation (proctitis), rectal pain and bleeding, straining, constipation and abdominal pain. The infection may also be accompanied by fever and malaise.
These can be treated with a three week course of antibiotics.
But sometimes the primary ulcer goes unnoticed, and if left untreated, this can progress to chronic infection with the formation of skin pouches (fistulas), abscesses, and narrowing of the anus as well as problems with the lymphatic system.