The first trichomonad species, Trichomonas tenax, was identified in 1773 by Miller, who found it in a culture of dental calculus.1 T. tenax has been associated with gingivitis. It is uncertain if the inflammatory process is attributed to T. tenax or if the organism simply inhabits the area.2
Donné first discovered and named Trichomonas vaginalis in 1836 after finding the the organism in genital secretions of both women and men. T. vaginalis' pathogenicity was initially thought to be non-pathogenic because a majority of infected patients were asymptomatic. The development of culture medium in the 1940s allowed more detailed study of the organism and its pathogenicity.3
In 1942, Hesseltine inoculated 70 pregnant volunteers with unadulterated T. vaginalis culture (10,000 to 120,000 trichomonads per inoculum.) Fifty-three patients were tested for trichomoniasis using vaginal smear and 17 received clinical observation. Seven of the 53 patients (13%) developed trichomoniasis shortly after inoculation. Two additional patients who tested negative for trichomoniasis prior to giving birth tested positive after giving birth.4
In 1953, Lanceley inoculated five male volunteers with 2 ml of T. vaginalis culture (2 million protozoa per ml) and another five with a control sample. Three of the five volunteers inoculated with culture developed urethritis from which T. vaginalis organisms were removed.5
Pentatrichomonas hominis (formerly Trichomonas hominis) was identified by Davaine in 1854 in human stool samples. P. hominis is found in the large intestine and has been associated with diarrheal problems. Like T. tenax, the pathogencity is unknown.6
The inoculation of T. tenax and P. hominis into the vagina generally does not produce infection. Recently, however, researchers using PCR reported the discovery of P. hominis in the vaginas of two women.7 The women tested negative for T. vaginalis and showed no symptoms. Likewise, although T. vaginalis in the mouth or intestines was not thought to foster infection, there have been several recent reports to the contrary.6
T. tenax is known to cause bronchopulmonary infections in patients with pre-existing pulmonary or debilitating disease.8 In 2003, Duboucher reported finding numerous T. vaginalis organisms in the lungs of a 41-year-old man infected with HIV.9
A number of trichomonad species infect animals. In cattle, Tritrichomonas foetus is a highly prevalent sexually transmitted infection that causes infertility, embryonic death, and abortion.10-12 In cats and dogs, T. foetus and Pentatrichomonas hominis cause chronic diarrhea.13,14 Tetratrichomonas gallinarum and Trichomonas gallinae are responsible for a wide range of diseases in birds.
- Miller L. Cited by Gsell, Mohr, Infektionskrankheiten. Vol IV (Springer, Heidelberg 1972).
- Spence M. Trichomoniasis. Contemp OB/GYN. 1992 Nov:132-141.
- Thomason JL, Gelbart SM. Trichomonas vaginalis. Obstet Gynecol. 1989 Sep;74(3 Pt 2):536-41.
- Hesseltine H. Experimental human vaginal trichomoniasis. J Infect Dis. 1942;71:127.
- Lanceley F, McEntegart MG. Trichomonas vaginalis in the male; the experimental infection of a few volunteers. Lancet. 1953 Apr 4;1(14):668-71.
- Rein MF, Muller M. Trichomonas vaginalis and trichomoniasis. In Holmes KK, editor. Sexually Transmitted Diseases. New York: McGraw Hill; 1990, pp. 481-492.
- Crucitti T, Abdellati S, Ross DA, Changalucha J, Dyck E, Buve A. Detection of Pentatrichomonas hominis DNA in biological specimens by PCR. Detection of Pentatrichomonas hominis DNA in biological specimens by PCR.
- Stratakis DF, Lang SM, Eichenlaub S, Löscher T, Stein R, Huber RM. Pulmonary trichomoniasis: diagnosis based on identification of irritation in bronchoalveolar lavage. Pneumologie. 1999 Dec;53(12):617-9.
- Duboucher C, Noël C, Durand-Joly I, Gerbod D, Delgado-Viscogliosi P, Jouveshomme S, Leclerc C, Cartolano GL, Dei-Cas E, Capron M, Viscogliosi E. Pulmonary coinfection by Trichomonas vaginalis and Pneumocystis sp. as a novel manifestation of AIDS. Hum Pathol. 2003 May;34(5):508-11.
- Rae DO, Crews JE, Greiner EC, Donovan GA. Epidemiology of Tritrichomonas foetus in beef bull populations in Florida. Theriogenology. 2004 Feb;61(4):605-18.
- Goodger WJ, Skirrow SZ. Epidemiologic and economic analyses of an unusually long epizootic of trichomoniasis in a large California dairy herd. J Am Vet Med Assoc. 1986 Oct 1;189(7):772-6.
- Parker S, Campbell J, McIntosh K, Gajadhar A. Diagnosis of trichomoniasis in 'virgin' bulls by culture and polymerase chain reaction. Can Vet J. 2003 Sep;44(9):732-4.
- Foster DM, Gookin JL, Poore MF, Stebbins ME, Levy MG. Outcome of cats with diarrhea and Tritrichomonas foetus infection. J Am Vet Med Assoc. 2004 Sep 15;225(6):888-92.
- Gookin JL, Birkenheuer AJ, St John V, Spector M, Levy MG. Molecular characterization of trichomonads from feces of dogs with diarrhea. J Parasitol. 2005 Aug;91(4):939-43.
