Clinical and Microbiological Aspects ofTrichomonas vaginalis

Abstract

SUMMARY Trichomonas vaginalis, a parasitic protozoan, is the etiologic agent of trichomoniasis, a sexually transmitted disease (STD) of worldwide importance. Trichomoniasis is the most common nonviral STD, and it is associated with many perinatal complications, male and female genitourinary tract infections, and an increased incidence of HIV transmission. Diagnosis is difficult, since the symptoms of trichomoniasis mimic those of other STDs and detection methods lack precision. Although current treatment protocols involving nitroimidazoles are curative, metronidazole resistance is on the rise, outlining the need for research into alternative antibiotics. Vaccine development has been limited by a lack of understanding of the role of the host immune response to T. vaginalis infection. The lack of a good animal model has made it difficult to conduct standardized studies in drug and vaccine development and pathogenesis. Current work on pathogenesis has focused on the host-parasite relationship, in particular the initial events required to establish infection. These studies have illustrated that the pathogenesis of T. vaginalis is indeed very complex and involves adhesion, hemolysis, and soluble factors such as cysteine proteinases and cell-detaching factor. T. vaginalis interaction with the members of the resident vaginal flora, an advanced immune evasion strategy, and certain stress responses enable the organism to survive in its changing environment. Clearly, further research and collaboration will help elucidate these pathogenic mechanisms, and with better knowledge will come improved disease control.

Characterization of an ecto-phosphatase activity in the human parasite Trichomonas vaginalis

“…The cell surface of Trichomonas vaginalis plays a major role in parasite-host cell adhesion, and nutrient acquisition (Petrin et al 1998). Adhesion of T. vaginalis to the epithelial cells in the vaginal environment is a critical step in the pathogenesis of this parasite (Heath 1981;Alderete and Pearlman 1984;Alderete and Garza 1985).…”

“…This disease presents various degrees of severity in women, from asymptomatic (nearly 50% of the cases) to extremely acerbic infections (Catterall 1974). Women who are infected during pregnancy are predisposed to premature rupture of the placental membranes, premature labor, and low-birth-weight infants (Minkoff et al 1984;Petrin et al 1998). Also linked to this disease are cervical cancer (Gram et al 1992;Zhang and Begg 1994), atypical pelvic inflammatory disease (Heine and McGregor 1993), infertility (Grodstein et al 1993), and enhanced HIV transmission (Sorvillo and Kerndt 1998).…”

“…This infection is globally considered to be one of the most frequent sexually transmitted diseases, with approximately 180-200 million cases annually (Petrin et al 1998). This disease presents various degrees of severity in women, from asymptomatic (nearly 50% of the cases) to extremely acerbic infections (Catterall 1974).…”

Trichomonas vaginalis virulence against epithelial cells and morphological variability: the comparison between a well-established strain and a fresh isolate

“…The parasitic protozoan Trichomonas vaginalis is the causative agent of human trichomoniasis, the most frequent, non-viral, sexually transmitted disease, accounting for approximately 180-200 million cases annually worldwide (Petrin et al 1998). Nearly 50% of infections in women are asymptomatic whereas the remaining ones may present vulvar pruritus, fetid, frothy or homogeneous vaginal discharge with leukorrhea and signs of colpitis macularis (Catterall 1972).…”

Mycoplasma hominis and Trichomonas vaginalis symbiosis: multiplicity of infection and transmissibility of M. hominis to human cells

“…A T. vaginalis infection is characterized by vaginal inflammation (Petrin et al 1998), and its pathogenicity mechanism involves the activity of pH-dependent pore-forming proteins and several proteases (Fiori et al 1997. Genital infection by M. hominis is associated with a variety of signs and symptoms, but the pathogenicity mechanisms of this bacterium are still unclear.…”