Trichomoniasis is a sexually transmitted disease (STD) caused by the parasite Trichomonas vaginalis. Although this infection is common worldwide, it has been considered a “neglected” parasitic infection, due to limited knowledge of its sequelae and associated costs. Infections are believed to be more common among women and with increasing age. Trichomoniasis also occurs more frequently in people with multiple sexual partners who also have other sexually transmitted infections. Conditions shown to be associated with T. vaginalis infection include: HIV acquisition and transmission, increased prevalence of other sexually transmitted infections, adverse outcomes of pregnancy (e.g., preterm delivery), and pelvic inflammatory disease.
The T. vaginalis parasite is a single-celled protozoan with 4 flagella at one end. Under a microscope, these flagella may be seen propelling the parasite. Infection may produce local inflammation as parasites adhere to mucosal tissue. T. vaginalis can be found in certain moist areas of the body, including male or female urethra, vagina and vulva. These parasites do not commonly infect the hands, mouth, or rectum. T. vaginalis parasites require a human host and do not affect any other animals. Although these parasites might be able to survive for a few minutes in damp environments outside the human body, there have been no proven cases of transmission via shared baths, toilets, or towels.
Clinical signs and symptoms of trichomoniasis are variable. Some individuals may be asymptomatic. Initial symptoms may develop within 5 to 28 days and may include itching or irritation, local erythema, burning sensation during urination or ejaculation, and vaginal or urethral frothy discharge that is classically yellowish or greenish and malodorous. Untreated infections can last for months to years, and symptoms might occur at any time. Available diagnostic methods include the highly sensitive nucleic acid amplification test (NAAT), wet mount microscopy, and culture. First-line therapy consists of either metronidazole or tinidazole. Treating patients and all sex partners can cure infection, reduce symptoms, and reduce transmission.
References:
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Schumann JA, Plasner S. Trichomoniasis [Updated 13 January 2019]. Treasure Island, FL, StatPearls Publishing. Available from: https://www.ncbi.nlm.nih.gov/books/NBK534826/.
