trikomonas

Trikomonas, commonly written Trichomonas, is a genus of flagellated protozoan parasites in the family Trichomonadidae. Species in this genus inhabit the genital and urinary tracts of humans and other mammals, the oral cavity of humans, and the digestive tract of birds, depending on the species. The best known member is Trichomonas vaginalis, a cause of trichomoniasis in humans.

Biology and life cycle: Trichomonas exists as a pear-shaped trophozoite about 7–12 μm long, with four anterior flagella, a trailing flagellum, an undulating membrane, and a ventral axostyle. It lacks mitochondria, using hydrogenosomes for energy under anaerobic conditions. Reproduction is by binary fission; there is no cyst stage in human infections. Transmission is mainly via direct contact during sex; in birds, transmission can occur through contaminated food or water and direct contact with infected birds.

Disease in humans: Trichomonas vaginalis causes trichomoniasis. Women commonly present with vaginitis, discharge, itching, and irritation; men may have urethritis or prostatitis. Many infections are asymptomatic. In pregnancy, infection can affect outcomes and increase susceptibility to other infections.

Diagnosis and treatment: Diagnosis relies on detection of motile trophozoites by microscopy, culture, or nucleic acid amplification tests. First-line treatment uses metronidazole or tinidazole; sexual partners should be treated to prevent reinfection. Resistance has been reported in some strains.

Prevention and epidemiology: Trichomoniasis is a widespread sexually transmitted infection worldwide. Prevention emphasizes safe sex practices, condom use, and regular screening in high-prevalence settings. In birds and nonhuman hosts, control relies on hygiene, management, and reducing exposure to infected animals.