Prevention or treatment: the benefits of Trichomonas vaginalis vaccine.

Trichomoniasis (infection with Trichomonas vaginalis) is the most common non-viral sexually transmitted disease (STI) in the world. Although treatment is available, most cases occur in developing countries, where accessing healthcare is difficult and facilities are limited. Additionally, infection is often asymptomatic and as such goes untreated, creating reservoirs of T. vaginalis that allow the disease to spread within the community. Because of this there has been little success in controlling the incidence of trichomoniasis, especially amongst the underprivileged. The development of a vaccine against T. vaginalis could reduce the human costs (pregnancy complications, infertility), medical costs (repeated doctor visits, increased susceptibility to human immunodeficiency virus (HIV) infection), and societal costs (stigma of STI, cycles of untreated infection) associated with trichomoniasis.

Treatment of infections caused by metronidazole-resistant Trichomonas vaginalis.

Infections with the sexually transmitted protozoan Trichomonas vaginalis are usually treated with metronidazole, a 5-nitroimidazole drug derived from the antibiotic azomycin. Metronidazole treatment is generally efficient in eliminating T. vaginalis infection and has a low risk of serious side effects. However, studies have shown that at least 5% of clinical cases of trichomoniasis are caused by parasites resistant to the drug. The lack of approved alternative therapies for T. vaginalis treatment means that higher and sometimes toxic doses of metronidazole are the only option for patients with resistant disease. Clearly, studies of the treatment and prevention of refractory trichomoniasis are essential. This review describes the mechanisms of metronidazole resistance in T. vaginalis and provides a summary of trichomonicidal and vaccine candidate drugs.