Lymphogranuloma Venereum Genetics

In 2004, medical professionals expressed concern regarding an outbreak of lymphogranuloma venereum (LGV) in the Netherlands and appearances in Canada and the U.S. West Coast. Now, it's being reported that 400 cases have been recorded in the UK through September 2006.

LGV is a sexually transmitted disease caused by the chlamydia bacteria which, until recently, was extremely rare outside of Africa and southeast Asia. The disease chiefly affects homosexual men.

In the latest news regarding LGV, an international group of researchers has performed a study of the chlamydia genome which is reported in this month's issue of Genome Research. According to senior author Professor Ian Clarke of the University of Southampton, the new gene catalogue will be a valuable research tool.

The researchers sequenced the genomes from two isolates of Chlamydia from patients with LGV - one obtained in California in the 1960s, and maintained as the major laboratory strain, and the other a recent isolate from a patient in London.

"The new sequences allow us to ask whether the recent increase in incidence of LGV is the result of emergence of a new and more virulent strain," continues Professor Clarke. "Our results suggest that the organism we find today is virtually identical with that isolated 40 years ago. It seems that we are not facing a novel, more dangerous organism."

The gene content of the two isolates is identical, with only around 500 differences between the two genomes. The research team found no evidence of novel genes or significant changes that might suggest a clear divergence between the two isolates.

Therefore, the recent outbreak of lymphogranuloma venereum cannot be attributed to a new strain of chlamydia bacteria. Current cases of LGV are caused by the same bug that caused LGV decades ago. As such, the recent outbreak can be explained by LGV having found a new way to piggyback itself through society.