Tetratrichomonas spp. and Pentatrichomonas hominis are not persistently detectable after intravaginal inoculation of estrous heifers

Virgin heifers (44) were intravaginally inoculated at estrus with low (106) or high (108) doses of live Tetratrichomonas sp., Pentatrichomonas hominis (P. hominis), or Tritrichomonas foetus (T. foetus). Controls were inoculated with Diamond's trypticase yeast extract maltose media. Genital infection was determined by culture of cervico-vaginal mucus (CVM) in Schneider's media and InPouch TF® as well as by polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP). The presence of trichomonads in fecal samples was determined by culture in Schneider's medium and PCR/RFLP. In CVM samples, tetratrichomonads were found by PCR/RFLP and Schneider's culture only sporadically at intermittent weeks. The presence of tetratrichomonads was not associated with the dose in the experimental vaginal inoculation since Tetratrichomonas sp. appeared more frequently in heifers inoculated with a low dose of tetratrichomonads than in heifers inoculated with a high dose of tetratrichomonads. Moreover, Tetratrichomonas spp. were isolated not only in heifers inoculated with tetratrichomonads but also in control heifers and in heifers inoculated with P. hominis. In feces, Tetratrichomonas spp. were frequently identified by culture in Schneider's and by PCR/RFLP in heifers of all groups. P. hominis was never found in CVM or feces by any method. Based on the common appearance of tetratrichomonads in feces and vaginal secretions, it appears that tetratrichomonads were detected periodically in the vagina of heifers as a consequence of repeated contamination from feces and not as a result of experimental infection. In summary, in this study, the strains of Tetratrichomonas sp. and P. hominis did not establish persistent infection in heifers.