Tritrichomonas foetus is a protozoan parasite that has been traditionally identified as a cause of reproductive tract disease in cattle and gastrointestinal tract infection in cats. Moreover, T. foetus is also well known as a commensal of the nasal cavity, intestines, and stomach in swine. In this review we describe T. foetus as a pathogen dangerous to more than one animal host, diagnostic and taxonomic aspects of this infection, and the extent to which isolates from different hosts share genetic identity.

Introduction: Abortion in cattle is a major source of economic losses for the agriculture sector. It can be due to infectious or non-infectious factors. Among infectious factors, parasites, bacteria, viruses, and fungi can be involved. The present work investigated the prevalence of the main infectious agents of abortion in Algerian cattle. Material and Methods: Altogether 278 non-aborting and 82 aborting cows were analysed. Results: The prevalence ranged from 0% for Tritrichomonas foetus to 15% for Neospora caninum. Additionally, a case-control study was performed to find the association between the presence of the pathogens and the occurrence of abortion in cows. The odds ratios were significant for Neospora caninum, bovine herpes virus 4, BVD virus, Brucella abortus, Salmonella Dublin, Leptospira interrogans serovar Hardjo, and Coxiella burnetii. Conclusions: The pathogens enumerated here could be major causes of abortion among Algerian cattle.

Tritrichomonas foetus is a protozoan parasite that has been traditionally identified as a cause of reproductive tract disease in cattle and gastrointestinal tract infection in cats. Moreover, T. foetus is also well known as a commensal of the nasal cavity, intestines, and stomach in swine. In this review we describe T. foetus as a pathogen dangerous to more than one animal host, diagnostic and taxonomic aspects of this infection, and the extent to which isolates from different hosts share genetic identity.

The primary objectives of this study were to estimate the prevalence of Campylobacter fetus subsp. venerealis (Cfv) and Tritrichomonas foetus in breeding bulls from a sentinel cohort of cow-calf herds in western Canada and to estimate the association between positive test status and non-pregnancy. The final objective was to evaluate the application of these tests when: i) screening bulls in the absence of a recognized problem with reproductive performance, and ii) testing for diagnosis of poor pregnancy rates. The crude apparent bull prevalence for Cfv was 1.1% [95% confidence interval (CI): 0.5% to 2.1%; 8/735] and herd prevalence was 2.6% (95% CI: 0.3% to 9.0%; 2/78). The crude apparent bull prevalence for T. foetus was < 0.001% (95% CI: 0.0% to 0.5%; 0/735) and herd prevalence was < 0.001% (95% CI: 0.0% to 4.6%; 0/78). Cows from herds where at least 1 bull was test positive for Cfv were 2.35 times more likely (95% CI: 1.01% to 5.48%; P = 0.047) to not be pregnant than those with no positive bulls. Polymerase chain reaction (PCR) testing of preputial material collected into phosphate-buffered saline (PBS) was recommended for screening for T. foetus when the pre-test probability of infection was > 1%. The same test for Cfv was not recommended for screening moderate- and low-risk herds due to the high risk of false positives. Tests for both T. foetus and Cfv can be used to investigate herds with reproductive problems when also ruling out other risk factors. Regardless of the type of test used, however, 3 negative tests are required to rule out infection in high-risk situations.

OBJECTIVE To investigate the effects of specific cysteine protease (CP) inhibitors on cytopathic changes to porcine intestinal epithelial cells induced by Tritrichomonas foetus isolated from naturally infected cats. SAMPLE T foetus isolates from 4 naturally infected cats and nontransformed porcine intestinal epithelial cells. PROCEDURES T foetus isolates were treated with or without 0.1 to 1.0mM of the CP inhibitors antipain, cystatin, leupeptin, and chymostatin and the vinyl sulfone inhibitors WRR-483 and K11777. In-gel gelatin zymography was performed to evaluate the effects of these inhibitors on CP activity of T foetus isolates. Each treated or untreated isolate was also cocultured with monolayers of porcine intestinal epithelial cells for 24 hours, and cytopathic effects of T foetus were evaluated by light microscopy and crystal violet spectrophotometry. RESULTS Results of in-gel gelatin zymography suggested an ability of WRR-483, K11777, and cystatin to target specific zones of CP activity of the T foetus isolates. These inhibitors had no effect on T foetus growth, and the cytopathic changes to the intestinal epithelium induced by all 4 T foetus isolates were significantly inhibited. CONCLUSIONS AND CLINICAL RELEVANCE This study revealed that certain protease inhibitors were capable of inhibiting regions of CP activity (which has been suggested to cause intestinal cell damage in cats) in T foetus organisms and of ameliorating T foetus–induced cytopathic changes to porcine intestinal epithelium in vitro. Although additional research is needed, these inhibitors might be useful in the treatment of cats with trichomonosis.

Thirty-five heifers were allotted to 3 groups. Group 1 (contro]) consisted of 10 heifers that were not vaccinated and were challenge exposed by breeding to infected bulls. Group 7 (natural challenge exposure) consisted of 10 heifers that were vaccinated and challenge exposed by breeding to infected bulls. Group 3 (experimental challenge exposure) consisted of 15 heifers that were vaccinated and challenge exposed by breeding to infected bulls and by intravaginal inoculation with 10(7) Tritrichomonas foetus. Total immunoglobulin concentrations and specific trichomonal antibodies were determined in serum and vaginal secretions of heifers, using radial immunodiffusion and ELISA procedures. Control heifers remained infected for a mean of 10.6 weeks (range, 0 to 18 weeks), and heifers of the natural and experimental challenge-exposure groups remained infected for 3.2 and 5.0 weeks, respectively (range, 0 to 12 weeks). Total serum and cervicovaginal mucus concentrations of IgM, IgA, IgG1, and IgG2 did not change significantly after vaccination or challenge exposure. However, ELISA titers of total trichomonal antibodies increased up to 1:10,000 (range, 1:400 to 1:10,000) in serum after vaccination, and increased approximately tenfold above background in cervicovaginal mucus. In serum, the predominant trichomonal antibody isotype was IgG1, although trichomonal IgA and IgM antibodies also increased. The predominant trichomonal antibody detected in cervicovaginal mucus was IgA. Antibody titers in serum and cervicovaginal mucus of vaccinated heifers were not increased by infection. However, in control heifers, the total local trichomonal antibody response increased three- to fivefold after infection. In these heifers, specific antibodies in serum were predominantly IgG1 and local (cervicovaginal) antibodies were predominantly IgA.

To test the efficacy of a polyvalent Tritrichomonas foetus vaccine, 130 nulliparous heifers were randomly assigned to either receive the test T. foetus vaccine or to serve as nonvaccinated controls. The polyvalent test vaccine consisted of a Campylobacter fetus/Leptospira canicola-grippotyphosa-hardjo-icterohaemorrhagiae-pamona bacterine containing 5 X 10(7) killed T. foetus/dose. The polyvalent control vaccine consisted of the aforementioned formulation without T. foetus. Heifers were administered 2 doses of control or experimental vaccine at 3-week intervals. Heifers were bred to T. foetus-infected bulls and their conception and pregnancy rates were determined throughout gestation. In addition, serum samples were analyzed to determine induced concentrations of antitrichomonal antibodies and vaginal secretions were sampled to determine T. foetus infection rates in control and vaccinated animals. One week after each of the 15-day breeding periods, 60% (6 of 10) of tested vaccinates and 80% (8 of 10) of tested control animals were T. foetus culture-positive. The mean duration of infection of vaccinates was 3.8 weeks (+/- 7.5 days), compared with 5.4 weeks (+/- 7.5 days) of infection for control heifers. All vaccinates developed increased immunofluorescence and serum neutralizing antibody titers following the first immunization, and had additional increases of at least fourfold in response to the second injection. In contrast, no consistent increase in immunofluorescence or serum neutralizing antibodies was observed in control animals. Conception rates were 89.2% for vaccinates and 85.9% for control animals 30 days after breeding and 80 to 90% of these remained pregnant 60 days after breeding. However, within the next 4 months, the pregnancy rate of control heifers decreased to 30% for those that had conceived. During the same 4-month period, more than 60% of vaccinated heifers remained pregnant. Significantly, 62.5% of heifers vaccinated against T. foetus produced calves, whereas only 31.5% of control heifers produced calves. These findings indicate that the polyvalent test vaccine induced an immune response that was effective in lowering the rate of T. foetus infection, decreasing the duration of infection, and reducing losses in calf production attributable to early fetal death and abortion caused by T. foetus infection.

Four virgin heifers were experimentally inoculated intravaginally with 7 X 10(6) Tritrichomonas foetus, and 2 heifers served as uninfected controls. The durations of infection were 13, 20, 21, and 28 weeks, respectively. An ELISA that used whole T foetus antigen was used to detect anti-T foetus immunoglobulins (IgA, IgG1, IgG2, and IgM) in vaginal, cervical, and uterine secretions, and sera during the course of infection. The vaginal and cervical antibody responses were characterized by significantly increased T foetus-specific IgA and IgG1 at 7 to 9 weeks of infection, whereas uterine IgA and IgG1 responses peaked at 10 to 12 weeks. The antibody response in serum was predominantly of the IgG1 and IgG2 subclasses. In all reproductive tract regions, IgA persisted at least until the time of T foetus clearance, and usually longer. The next most persistent isotype was IgG1, lasting longest in the vagina, then cervix, and for the shortest time in the uterus. In local secretions, IgG2 was seen only transiently, increasing at weeks 13 to 15 in the vagina, and at weeks 10 to 12 in the cervix. Little IgM, relative to that present before infection, was detected in any secretion or serum, although cervical secretions had the greatest amount. Eight to 12 weeks after clearance, the 4 experimental heifers were inoculated intravaginally with 1 x 10(5) T foetus, transient infections (2 to 3 weeks' duration) were established in only 2 of 4 heifers, as determined by culturing of reproductive tract secretions. The lag times of antibody responses during this reinfection were shorter than in the initial infection, and ELISA optical densities were at least as high as during the primary infection, suggesting an anamnestic response.

The current diagnostic test for Tritrichomonas foetus involves the culture of collected preputial or vaginal samples. In an earlier study, which evaluated sampling tools for use with bulls, it was observed that the sensitivity of the diagnostic test was higher for 2nd samples collected from the right side of the prepuce than it was for samples collected 1st from the left side. The study described in this paper was conducted to evaluate which of these factors was responsible for the effect on diagnostic sensitivity. Twenty-nine bulls infected with T. foetus were repeatedly sampled in a 2-factor cross-over design. Samples taken from the right side of the prepuce were 4 times as likely to be positive as samples taken from the left side (P = 0.03). Other factors did not have a significant effect on the outcome of the diagnostic test. Unexpected factors may affect the sensitivity of the diagnostic test for T. foetus.

Analysis of protein and antigen profiles of Tritrichomonas foetus isolates from cattle from 5 western states was accomplished sodium dodecyl sulfate polyacrylamide-gel electrophoresis, immunoblot, immunoprecipitation, and fluorography techniques. Total protein profiles of all isolates were compared by Coomassie brilliant blue staining of T foetus protein samples prepared by 4 protein-extraction methods. Antigenic tritrichomonas proteins were identified by immunoblot assay with polyclonal bovine or rabbit anti-T foetus serum. Additionally, [14C]glucosamine-labeled T foetus was used for total and antigenic glycoprotein analyses. Detectable differences in the composition of total proteins or antigenic tritrichomonal proteins were not observed among all isolates. However, intensity differences in some antigenic protein bands were apparent. Bovine and rabbit sera from immunized animals possessed antibodies to the same antigenic tritrichomonal proteins. Each T foetus isolate contained 4 to 7 molecular weight size classes of glycoprotein, which were labeled by [14C]glucosamine; however, only 3 to 4 glycoproteins were identified as antigens by bovine or rabbit antiserum.