Background:
Lymphogranuloma venereum (LGV) was rarely diagnosed in the UK prior to 2004. Since then there has been a large number of cases in men who have sex with men (MSM).

Objective:
To describe LGV in the UK.

Method:
In October 2004 we established a national diagnostic and surveillance system for LGV. Clinicians and laboratories were alerted. Detailed surveillance forms were completed for confirmed cases.

Result:
From 2004 to March 2006, 341 cases of LGV were diagnosed. Surveillance forms have been received for 283. All but three cases were in MSM, and concentrated in London (73%) and Brighton (14%) with the rest distributed across the UK. The majority of cases (94%) presented with symptoms of proctitis; 30% also had systemic symptoms; 3% had urogenital symptoms, 3% were asymptomatic. Time from symptoms to presentation ranged from less than a day to over 18 months, median 13 days. There were high levels of coinfection with other STI: 76% had HIV infection, including 9 newly diagnosed; less than half were on HAART. 11% were known to have HCV, 26% had one or more additional STI.
Cases presenting in 2004 were significantly more likely than those presenting in 2005-6 to report sexual contacts in or from the Netherlands (20% compared with 3%, p=0.002). Information on venues for meeting new partners was available for 113 men. Eighty (71%) reported meeting new partners at sex on premises venues or sex parties, and 29 (26%) via the Internet.

Conclusion:
There is a sustained outbreak of LGV in MSM in the UK. The overlap with HIV and other STI suggests transmission in a very densely connected sexual network.

Implications:
We need more information on the prevalence of rectal chlamydia, including LGV, in MSM to inform screening guidelines. Interventions at key venues are being undertaken. National surveillance can help identify new and re-emerging infections.