Difference in effect of dog seminal fluid and human seminal fluid and semen on in vitro survival of Trichomonas vaginalis.

The authors examined the ability of dog seminal fluid to serve as an animal model in order to study survival of Trichomonas vaginalis in human urogenital secretions. Two strains were used: SVI-1, a recent isolate from a male patient, and ATCC 30001, a strain that has been cultured for many years. The authors incubated the T. vaginalis strains in dog seminal fluid, human seminal fluid, and human semen, at 37 degrees C for 6, 12, and 24 hrs. For both strains, survival in dog seminal fluid was much poorer than that in human semen and seminal fluid, zero survival being noted at 24 hrs. The SVI-1 strain survived significantly better than ATCC 30001 in all secretions. Data from experiments using isolates from two female patients, but incubated in human seminal fluid alone, agreed with results obtained with SVI-1. Dog seminal fluid may not be a suitable substitute for human secretions in T. vaginalis studies, and long-term culture may decrease the ability of T. vaginalis to survive in the male urogenital tract.