Acquisition and retention of viruses by Trichomonas vaginalis.

Recently described occurrence of virus-like particles (VLP) in some strains of Trichomonas vaginalis suggests the possibility that the pathogenic significance of this organism may be broadened by its potential for viral transmission. Inasmuch as neither the source nor the host range of the VLP are known, any hazard which they may present for man cannot be estimated. A model has been established for the study of acquisition of known human viruses by T vaginalis. Tissue cultures were infected with two reoviruses and a fresh isolate of genital herpes simplex virus (HSV). A squirrel monkey reovirus was also included in the study. T vaginalis was inoculated into the virus cultures three days later. The progress of virus acquisition by the trichomonads was monitored by transmission electron microscopy and by culture. Virus-containing cell fragments were engulfed by trichomonads and internalised in vacuoles. After digestion of cellular debris only virus particle aggregates were retained. Viable reoviruses were recovered from the trichomonads for nine days, and HSV for six days. The results suggest the possibility of transmission of at least some viruses by T vaginalis.