Lymphogranuloma Venereum Epidemiology

Lymphogranuloma venereum represents an uncommon sexually-transmitted disease caused by the invasive serovars of an obligate intracellular pathogen Chlamydia trachomatis. It belongs to the genital ulcer disease spectrum (alongside syphilis, chancroid and herpes simplex type 2), and the main site of action of the putative organism are regional lymph nodes.

The only reservoir for Chlamydia trachomatis is human, and the disease is transmitted via sexual intercourse when a direct contact with an open lesion ensues (albeit indirect or non-sexual transmission is sporadically described in the literature). Untreated patients remain infectious for years, while the spread of the disease is further perpetuated by poor hygienic conditions.

Although lymphogranuloma venereum most likely affects both males and females equally, the condition is more commonly observed in men. This is probably due to the fact that early disease manifestations are more discernible in men; therefore, the diagnosis is established more readily.

CDC microbiologist Dr Cheng-Yen Chen, was shown preparing a pyrosequencing experiment in order to differentiate between Chlamydia trachomatis L-serovars responsible for lymphogranuloma venereum (LGV), and other chlamydial serovars. Organisms of the same genus are further subdivided into serovars, or serotypes, which group these organisms based upon their constituent intracellular antigenic profiles. Image Credit: CDC/ Hsi Liu, Ph.D., MBA, James Gathany

Endemic Regions for Lymphogranuloma Venereum

Lymphogranuloma venereum is still endemically present in heterosexuals in West and East Africa, certain parts of Southeast Asia, South America, India, and the Caribbean basin. It usually appears in the classic form of the disease, manifesting with genital ulcers and lymphadenopathy (but without the presence of proctitis).

Clinical case series of patients presenting with genital ulcer suggest that lymphogranuloma venereum is not a common cause of genital ulcers in Africa. However, ten percent of all patients with buboes (i.e. swollen, tender and enlarged lymph nodes) that present to STD clinics in Bangkok are harboring these invasive serovars of Chlamydia trachomatis, while large epidemics were reported among the users of crack cocaine in the Bahamas.

The prevalence of the disease in Jamaica in 1996 was 2.63 percent (as determined by cross-sectional surveys), while in Madagascar eight percent of genital ulcer diseases in 1997 were diagnosed clinically as lymphogranuloma venereum. In Nigeria, lymphogranuloma venereum was the most common cause of genital ulcerative changes for years in women that attended STD clinics.

Spread across Europe and the United States

Until 2003 only sporadic cases of the disease were reported in Europe and North America – mainly among travelers, military personnel and seafarers who were infected during their visit to endemic regions of the world. These infections were, therefore, considered imported.

However, after 2003 the disease became established mostly among men who have sex with men (MSM) that exhibit high-risk sexual behavior. The predominant clinical presentation was proctitis, and the spread started in the Netherlands, which was followed by other Western European countries, North America. Based on the data between 2004 and 2008, there is evidence that the disease may be endemic among MSM in the United Kingdom.

In the beginning, no national reporting or universal surveillance was instituted in the United States, thus the true incidence remained unknown. However, soon after European experience the Centers for Disease Control (CDC) offered assistance for lymphogranuloma venereum testing, and a study from 2011 that evaluated multiple countries in the US found that one percent or less of all rectal swabs obtained from MSM were positive for Chlamydia trachomatis L serovars.

Almost all those cases of lymphogranuloma venereum have been caused by the L2b variant of Chlamydia trachomatis (conveniently dubbed “the Amsterdam variant”), and usually confined to individuals co-infected with human immunodeficiency virus (HIV) and/or hepatitis C.

The number of lymphogranuloma venereum in MSM populations is still on the rise. Moreover, more recent reports of endemically acquired disease among heterosexual individuals in the Netherlands, France and some other Western European countries means that transmission is occurring outside the initial close group – therefore close monitoring is warranted.