Sharp increase in LGV cases in the UK; risk factors identified

There were more than twice as many cases of lymphogranuloma venereum (LGV) in the first quarter of 2010, compared to the same period in 2009, Cassandra Powers of the Health Protection Agency announced at the joint conference of the British HIV Association (BHIVA) and the British Association for Sexual Health and HIV (BASHH) last week.

LGV is a previously rare sexually transmitted infection, caused by specific strains of Chlamydia. If left untreated, symptoms can be complex and severe, including proctitis (inflammation of the anus or rectum).

Cases were first noticed in gay men in 2004 and 2005, but by 2008 there was hope that this new epidemic was levelling off. Almost all cases of LGV are in gay or bisexual men, and three quarters of those infected are HIV-positive.

The new data come from national surveillance systems and show the monthly number of cases increasing each month, from September 2009 onwards. In the first quarter of 2010, there were 113 cases, a 209% increase from the first quarter of 2009.

Cases continue to be concentrated in London, Manchester and Brighton, but not exclusively so. Powers said that the increase could not be attributed to an increase in the number of men being tested for LGV.

Also at the conference, Helen Ward presented preliminary data from the LGV-net study on the possible risk factors for LGV acquisition. This case-control study recruited 73 men with LGV from six UK clinics, and compared them to two control groups. The first control group was gay men with no symptoms attending sexual health screening; the second was gay men who had similar symptoms to the men with LGV, but who did not have LGV itself.

Despite the relatively small numbers of men in the study, a large number of factors were associated in the multivariate analysis with a statistically significant risk of having LGV.

Compared to men with no symptoms, the following factors were significant: having HIV (odds ratio 2.7), fisting (8.5), receptive unprotected anal intercourse (3.0), insertive unprotected intercourse (1.7), using backrooms (1.6), using saunas (3.3), using the internet to meet partners (1.8) and taking crystal meth (2.7).

In the final model, the two factors found to be independently associated with having LGV were fisting and using a sauna.

Compared to men with symptoms, the following were significant: having HIV (1.5), having more than ten partners (1.6), receptive unprotected anal intercourse (1.4), insertive unprotected intercourse (4.8), water sports (1.8), white ethnicity (2.5), using backrooms (2.0), using the internet to meet partners (1.1), attending a sex party (1.3), taking crystal meth (1.3) and taking Viagra (1.2).

In the final model, the only factor that was independently associated with having LGV was unprotected insertive anal intercourse. However Ward pointed out that almost all men had acquired LGV rectally. She said that analysing what the real risk factors are was challenging as so many factors correlate with each other.

She suggested that the association with HIV infection was not a biological factor, but that having HIV could be a determinant of certain behaviours: sero-sorting and being in dense sexual networks where LGV is being transmitted.

Ward outlined her provisional understanding of how LGV was being transmitted: “We think this relates to having very dense sexual networks, but particularly simultaneous contacts at parties and saunas where men are having both insertive and receptive anal sex, which may be the explanation for why we are not seeing so much urogenital LGV. We are actually getting rectal to rectal transmission by way of condoms and fisting with multiple partners in a single sexual episode.”

Both speakers recommended greater health promotion activity to increase awareness of LGV, with Helen Ward specifying that this should include targeted information about the risks in multi-partner situations and ways to reduce those risks. Cassandra Powers recommends that LGV testing should be offered during routine clinical care to HIV positive gay men who have symptoms of LGV (for example proctitis) or who have chlamydia.