Isolation, cultivation, low temperature preservation, and infectivity titration of Trichomonas vaginalis.

The diagnosis of Trichomonas vaginalis (Donne, 1837) infection by direct recognition of the parasite is comparatively easy in the acute phase in the female, more difficult in the male and in the female in the non-acute phase. Because of this difficulty conclusive epidemiological studies on T. vaginalis infection are few. Burch, Rees, and Reardon (1959) have contributed an informative study of the prevalence and transmission of T. vaginalis among groups of women in Washington, D.C., U.S.A., and their spouses, using culture for diagnosis. We considered that immunological studies might improve the diagnosis of T. vaginalis infection and facilitate studies on the epidemiology and clinical significance of this organism. Kerr and Robertson, who published detailed immunological studies (conveniently summarized in Robertson, 1963, and Kerr, 1964) on Trichomonas foetus (Riedmuller, 1928) in the ox, established that the organism occurred as two different serological types. Kott and Adler (1961), by agglutination and agglutinin-absorption tests, distinguished eight different serotypes among nineteen strains of T. vaginalis and two among five strains of T. hominis (Davaine, 1860). They found, further, that two strains of T. vaginalis of different antigenic types changed, both to the same other type, after the cultures had been bacterially contaminated and then "cleaned" with antibiotics. Lindgren and Ivey (1964), assessing virulence by the results of intraperitoneal inoculation of mice, indicated that T. vaginalis strains might lose their virulence on prolonged serial passage in culture. They thought that virulence might be conserved by viable preservation of the organisms by freezing. It appeared, therefore, that an essential preliminary to comparative immunological studies on