It is known that physicochemical conditions (e.g., pH, temperature, and ionic strength) affect the size of trichomonads. In this study, the sizes of 4 isolates of Trichomonas vaginalis cultured for more than a year (called "old T") and 3 isolates freshly isolated from vaginitis cases (called "fresh T") were compared by scanning electron microscopy. Although the fresh T had shorter body length, body width, and flagellar length than old T, total length (about 26 microm), including body length, flagella length, and axostyle length was almost the same in the 2 groups. A striking difference was observed between the axostyles of the 2 groups; the axostyle length of the fresh T (8.2 microm) was more than twice as long as that of the old T (4.0 microm). However, in several parasitology textbooks, the length of T. vaginalis is said to vary widely from 7 to 32 microm, and its undulating membrane is said to extend about half way (53.5%) to the posterior end of the body. On the other hand, in our study, the undulating membrane was observed to extend more than 3/4 of the body length (72.1%) in old T, whereas in fresh T it could not be measured. Taken together, we suggest that T. vaginalis averages 26 (21-32) microm in total length, with 9.5 (7.4-11.4) microm of body length and 6.8 (5.3-7.7) microm of width, and its undulating membrane extending 3/4 of its body length. Therefore, these findings may provide useful information for morphological characteristics of T. vaginalis.
*Biometry ; Female ; Humans ; *Microscopy, Electron, Scanning ; Organelles/ultrastructure ; Trichomonas Infections/parasitology ; Trichomonas vaginalis/*cytology/isolation & purification/*ultrastructure

Vaginal trichomoniasis, caused by Trichomonas vaginalis, is the most common sexually transmitted disease. More than 170 million people worldwide are annually infected by this protozoan. In the Republic of Korea, 10.4% of women complaining of vaginal symptoms and signs were found to be infected with T. vaginalis. However, despite its high prevalence, the pathogenesis of T. vaginalis infection has not been clearly characterized although neutrophil infiltration is considered to be primarily responsible for the cytologic changes associated with this infection. We hypothesized that trichomonads in the vagina sometime after an acute infection secrete proteins like excretorysecretory product that have a chemotactic effect on neutrophils, and that these neutrophils are further stimulated by T. vaginalis to produce chemokines like IL-8 and GRO-alpha, which further promote neutrophil recruitment and chemotaxis. Thus, neutrophil accumulation is believed to maintain or aggravate inflammation. However, enhanced neutrophil apoptosis induced by live T. vaginalis could contribute to resolution of inflammation. Macrophages may constitute an important component of host defense against T. vaginalis infection. For example, mouse macrophages alone and those activated by lymphokines or nitric oxide are known to be involved in the extracellular killing of T. vaginalis. In the host, T. vaginalis uses a capping phenomenon to cleave host immunoglobulins with proteinases and thus escape from host immune responses. Recently, we developed a highly sensitive and specific diagnostic polymerase chain reaction (PCR) technique using primers based on a repetitive sequence cloned from T. vaginalis (TV-E650), and found that the method enables the detection of T. vaginalis at concentrations as low as 1 cell per PCR mixture.
Trichomonas vaginalis/cytology/*isolation & purification/pathogenicity ; Trichomonas Vaginitis/drug therapy/*epidemiology/parasitology ; Korea/epidemiology ; Humans ; Female ; Animals