Trichomonad Infection Research Articles

Pulmonary infection with an unusual microorganism.

Pulmonary trichomoniasis is an underdiagnosed disease. In most cases, there is an underlying clinical condition related to immunosuppression. The results of molecular biology techniques indicate that trichomonad infections have been significantly underestimated. A 7-year-old girl with a medical history of suspected juvenile rheumatoid arthritis presented with a fever, chills, and a productive cough. Her chest computed tomography scan indicated a pericardial effusion and consolidation in the left lower lobe. In direct microscopy of the bronchoalveolar lavage fluid, we identified a motile and flagellated organism. Based on the morphology, size, and rolling motility, we identified this organism as Trichomonas hominis. The patient's fever stopped after 3 days of intravenous metronidazole administration. In immunocompromised patients with evidence of pneumonia, sputum or bronchial samples should be examined more carefully. The possibility of unusual pathogens should be considered if they do not respond to antibacterial treatments.

Prevalence of intestinal trichomonads in captive non-human primates in China.

Trichomonads are protozoan symbionts with the capacity to infect vertebrates including humans and non-human primates (NHPs), sometimes with pathogenic effects. However, their diversity and prevalence in NHPs in China are poorly understood. A total of 533 fecal samples were collected from captive NHPs in Yunnan Province, China, of which 461 samples from Macaca fascicularis and 72 from Macaca mulatta. Trichomonadidae species were identified using PCR amplification of the ITS-1/5.8S/ITS-2 sequences. The overall prevalence of trichomonads in NHPs was determined to be 11.4% (61/533), with gender, diarrhea, and region identified as potential risk factors for the infections. Sequence alignment and phylogenetic analysis identified three species of trichomonads, i.e., Trichomitopsis minor (n=45), Pentatrichomonas hominis (n=11), and Tetratrichomonas sp. (n=5). To the best of our knowledge, this is the first study to report Trichomitopsis minor infection in NHPs in China. Of note, Pentatrichomonas hominis is generally recognized as a parasitic organism affecting humans. Collectively, our results suggest that NHPs are potential sources of zoonotic trichomonad infections, highlighting the importance of surveillance and control measures to protect human and animal populations.

Cellular and humoral components of the immune system in trichomonas infection with metronidazole

Introduction. Despite the annual increase in infectious pathologies, including trichomoniasis, there is still insufficient study of the key processes of their development and progression, as well as the complexity of diagnosis and treatment. The aim of the study was to evaluate the role of the cellular and humoral component of the immune system in trichomonad infection against the background of metronidazole administration. Materials and methods. One hundred patients with trichomoniasis who received metranidazole for seven days were examined. Patients in the first group (n=50) received 500 mg twice daily. Patients in the second group (n=50) received 2 g once daily. Clinical and laboratory methods were used in the study. Results and discussion. It was found that early term trichomonad infection caused by T. Vaginalis, is accompanied by pronounced changes in the structure of the immune system in the form of activation of both cellular (reliable increase in CD3+, CD4+, CD8+), and humoral (reliable increase in phagocytic activity of neutrophils, inhibition — IgG and IgA, activation of IgE) immune links. The above changes were associated with the applied metranidazole regimen. It was found that the administration of this drug by 500 mg orally twice a day was more effective than by 2 g once a day. It was found that the imbalance of the immune system in the first group was reversible, the studied parameters approached the norm on the seventh day, and in the second group — persistent (most parameters exceeded the reference level at the end stage). Conclusion. The body's immune cascade, consisting of cellular and humoral components, in patients with trichomonad infection should be considered as an object for further scientific search for effective ways to manage it.

Composite thermoresponsive hydrogel with auranofin-loaded nanoparticles for topical treatment of vaginal trichomonad infection.

Trichomonas vaginalis is responsible for the most common non-viral sexually-transmitted disease worldwide. Standard treatment is with oral nitro-heterocyclic compounds, metronidazole or tinidazole, but resistance to these drugs is emerging and adverse effects can be problematic. Topical treatment offers potential benefits for increasing local drug concentrations and efficacy, while reducing systemic drug exposure, but no topical strategies are currently approved for trichomoniasis. The anti-rheumatic drug, auranofin (AF), was recently discovered to have significant trichomonacidal activity, but has a long plasma half-life and significant adverse effects. Here, we used this drug as a model to develop a novel topical formulation composed of AF-loaded nanoparticles (NP) embedded in a thermoresponsive hydrogel for intravaginal administration. The AF-NP composite gel showed sustained drug release for at least 12 h, and underwent sol-gel transition with increased viscoelasticity within a minute. Intravaginal administration in mice showed excellent NP retention for >6 h and markedly increased local AF levels, but reduced plasma and liver levels compared to oral treatment with a much higher dose. Furthermore, intravaginal AF-NP gel greatly outperformed oral AF in eliminating vaginal trichomonad infection in mice, while causing no systemic or local toxicity. These results show the potential of the AF-NP hydrogel formulation for effective topical therapy of vaginal infections.

What is known about Tritrichomonas foetus infection in cats?

Tritrichomonas foetus is a parasite that has been definitively identified as an agent of trichomonosis, a disease characterized by chronic diarrhea. T. foetus colonizes portions of the feline large intestine, and manifests as chronic and recurrent diarrhea with mucus and fresh blood, which is often unresponsive to common drugs. Diagnosis of a trichomonad infection is made by either the demonstration of the trophozoite on a direct fecal smear, fecal culture and subsequent microscopic examination of the parasite, or extraction of DNA in feces and amplification by the use of molecular tools. T. foetus is commonly misidentified as other flagellate protozoa such as Giardia duodenalis and Pentatrichomonas hominis. Without proper treatment, the diarrhea may resolve spontaneously in months to years, but cats can remain carriers of the parasite. This paper intends to serve as a source of information for investigators and veterinarians, reviewing the most important aspects of feline trichomonosis, such as trichomonad history, biology, clinical manifestations, pathogenesis, world distribution, risk factors, diagnosis, and treatment.

Idiopathic Colitis in Rhesus Macaques Is Associated With Dysbiosis, Abundant Enterochromaffin Cells and Altered T-Cell Cytokine Expression.

Idiopathic chronic diarrhea (ICD) is a common ailment affecting captive rhesus macaques ( Macaca mulatta). ICD cases are characterized by diarrhea in the absence of commonly identified diarrheal pathogens and multiple recurrences even after supportive therapy. Histologically, the disease is characterized by lymphoplasmacytic colitis. We identified 35 rhesus macaques euthanized for ICD during a 7-month period and described demographic, clinical, histologic, and immunologic commonalities. We found a trend of historic Campylobacter spp. and trichomonad infections. Furthermore, rhesus macaques with ICD demonstrated loss of normal colonic adherent bacterium, identified in this study as Helicobacter macacae; increased abundance of Pentatrichomonas hominis; and increased frequency of colonic serotonin-positive enterochromaffin cells. Interestingly, colonic and ileal T-helper cells of animals with ICD manifested decreased capacity for expression of certain cytokines, in particular interleukin (IL)-4 and IL-13. These data further describe a common ailment and suggest new avenues to identify complex interactions involved in the etiology of recurring diarrhea in young rhesus macaques.

Synthesis and Preliminary Antimicrobial Analysis of Isatin-Ferrocene and Isatin-Ferrocenyl Chalcone Conjugates.

In this study, we outline the synthesis of isatin–ferrocenyl chalcone and 1H-1,2,3-triazole-tethered isatin–ferrocene conjugates along with their antimicrobial evaluation against the human mucosal pathogen Trichomonas vaginalis. The introduction of a triazole ring among the synthesized conjugates improved the activity profiles with most of the compounds in the library, exhibiting 100% growth inhibition in a preliminary susceptibility screen at 100 μM. IC50 determination of the most potent compounds in the set revealed an inhibitory range between 2 and 13 μM. Normal flora microbiome are unaffected by these compounds, suggesting that these may be new chemical scaffolds for the discovery of new drugs against trichomonad infections.

Aberrant and accidental trichomonad flagellate infections: rare or underdiagnosed?

The clinical significance and frequency of human infections with trichomonad flagellates in aberrant locations (locations other than the predilection sites) and accidental infections (infections with non-human trichomonads) are unclear. The total number of case reports in the literature is low, with the identification of the infection largely the outcome of investigations for the cause of clinical signs. At least seven species have been identified in either aberrant or accidental infections, with these infections occurring worldwide. Results of prospective and retrospective surveys of adults with respiratory disease suggest that aberrant and accidental trichomonad infections are less rare than the number of case reports suggest, with Trichomonas tenax being the most frequent. Surveys of neonates and infants suggest that aberrant Trichomonas vaginalis infections can be higher and more serious than suggested by the few case reports. The density and location of infection might be as important, if not more so, than species in determining pathogenicity. Molecular diagnostic methods including DNA sequencing can be used to better diagnose infections and enable identification to assist in determining the clinical significance of different species. Raising awareness of these infections among clinicians and adding them to their differential lists are strongly suggested.

Phytochemical-rich foods inhibit the growth of pathogenic trichomonads

BackgroundPlants produce secondary metabolites that often possess widespread bioactivity, and are then known as phytochemicals. We previously determined that several phytochemical-rich food-derived preparations were active against pathogenic foodborne bacteria. Trichomonads produce disease (trichomoniasis) in humans and in certain animals. Trichomonads are increasingly becoming resistant to conventional modes of treatment. It is of interest to test bioactive, natural compounds for efficacy against these pathogens.MethodsUsing a cell assay, black tea, green tea, grape, pomegranate, and jujube extracts, as well as whole dried jujube were tested against three trichomonads: Trichomonas vaginalis strain G3 (found in humans), Tritrichomonas foetus strain D1 (found in cattle), and Tritrichomonas foetus-like organism strain C1 (found in cats). The most effective of the test substances was subsequently tested against two metronidazole-resistant Trichomonas vaginalis strains, and on normal mucosal flora.ResultsBlack tea extract inhibited all the tested trichomonads, but was most effective against the T. vaginalis organisms. Inhibition by black tea was correlated with the total and individual theaflavin content of the two tea extracts determined by HPLC. Metronidazole-resistant Trichomonas vaginalis strains were also inhibited by the black tea extract. The response of the organisms to the remaining preparations was variable and unique. We observed no effect of the black tea extract on common normal flora bacteria.ConclusionsThe results suggest that the black tea, and to a lesser degree green tea, grape seed, and pomegranate extracts might present possible natural alternative therapeutic agents to treat Trichomonas vaginalis infections in humans and the related trichomonad infections in animals, without negatively affecting the normal flora.

Non-cultured faecal and gastrointestinal seed samples fail to detect Trichomonad infection in clinically and sub-clinically infected columbid birds

Trichomonosis, caused by the protozoan Trichomonas gallinae, is an emerging infectious disease in finches, and is more commonly found in columbids and raptors. Infections can be sub-clinical or cause morbidity and mortality, but the parasite is currently only detectable by incubation of an oral swab. Here, we test whether T. gallinae parasites can be detected by PCR from faecal or non-cultured samples from the oral cavity and gastrointestinal tract of infected Turtle Doves (Streptopelia turtur). PCR did not detect T. gallinae parasites in any faecal samples screened, and in only 1 of 11 oral/gastrointestinal samples (from the mouth of a nestling suspected to have died from trichomonosis). We conclude that both oral swabs and parasite culture are still necessary to detect the sub-clinical presence of T. gallinae infection in birds.

Syrian hamsters (Mesocricetus auratus) with simultaneous intestinal Giardia sp., Spironucleus sp., and trichomonad infections

A commercial facility producing hamsters with a history of infection by dwarf tapeworm (Hymenolepis nana) submitted 15 animals for necropsy and postmortem parasitological and microscopic examination. No tapeworms were detected grossly or microscopically. Fecal examination including gastrointestinal mucosal smears demonstrated mixed intestinal bacteria and low numbers of Giardia sp. Histologic examination of small intestine demonstrated filling of the small intestinal crypts by large numbers of 7-9 µm × 3 µm, rod to crescent or teardrop-shaped flagellates consistent with Spironucleus sp. These organisms had two 1-µm, basophilic, oval nuclei and multiple superficial flagella-like structures. Much larger 10-15 µm × 8-10 µm, oval to pear-shaped organisms were also present in lower numbers and usually located with the crypts. These larger flagellates had multiple flagella and a basophilic rod-shaped nucleus. The larger flagellates included Giardia sp., which had an intimate interface with the surface of the mucosal epithelium, bilaterally symmetry, and binucleation. Lower numbers of trichomonads were also present and were distinguished by an undulating surface membrane and a single nucleus. The mucosa was hyperplastic and moderately inflamed. Although the tapeworm infection was resolved, diagnosis of multiple intestinal flagellates by fecal examination is complicated by the varying sensitivity and diagnostic accuracy of different types of fecal analysis for different flagellate types. Key differences in the morphology and location of the different types of flagellates as observed by histology of intestinal tissues provide important additional diagnostic information to distinguish trichomonads, Spironucleus sp., and Giardia sp.

Prevalence, risk factors of infection and molecular characterization of trichomonads in puppies from French breeding kennels

The trichomonad species Tritrichomonas fetus and Pentatrichomonas hominis were recently identified in the feces of dogs with diarrhea. However the prevalence and pathogenicity of these parasites in the canine population still remained poorly resolved. Therefore the aim of the present study was (1) to determine the prevalence of trichomonads infecting puppies living in French breeding kennels, (2) to confirm the predominance of P. hominis in dogs, (3) to investigate the genetic diversity of P. hominis isolates identified in the French canine population and (4) to evaluate the risk factors for infection by P. hominis and the influence of the parasite on feces consistency. A total of 215 both diarrheic and non-diarrheic puppies from 25 French breeding kennels were included in this epidemiological survey. Fecal samples from each puppy were examined for 6 gastrointestinal pathogens: parvovirus type 2 (CPV2), coronavirus, Toxocara canis, Cystoisospora ohioensis-complex, Cystoisospora canis, and Giardia intestinalis. A part of each collected stool was also tested for the presence of motile trichomonads by microscopy after culturing. The prevalence of trichomonad infection was 15.8% (34/215) among puppies and 20% (5/25) among breeding kennels. DNA from 26 of the 34 positive samples was successfully amplified using a trichomonad-specific primer pair. Analysis of the sequences of PCR products indicated that P. hominis was the only trichomonad infecting the canine population. All the puppies infected with P. hominis belonged to large breed dogs. Moreover, puppies from large breeding kennels, excreting a high level of G. intestinalis and/or excreting a high level of C. canis oocysts showed a higher probability of being positive for P. hominis infection. Univariate analysis also revealed an increased risk for P. hominis infection in puppies with abnormal feces. However, in a multivariate analysis, CPV2 was the only gastrointestinal pathogen associated with abnormal feces. Since enteropathogens were commonly found in dogs infected by P. hominis, the pathogenic potential of this trichomonad species remained uncertain and has to be further evaluated by experimental infection studies.

Trichomonad Infection in Endemic and Introduced Columbids in the Seychelles

Island endemic avifaunas face many threats, including the now well-documented impacts of pathogens. The impacts of pathogens on the endemic Seychelles avifauna, however, have been little studied. The protozoan parasite Trichomonas gallinae has been shown to reduce survival and reproductive success of the endemic Pink Pigeon Columba mayeri on the nearby island of Mauritius. I investigated trichomonad infection prevalence and pathogenicity in endemic Seychelles Blue Pigeons, Alectroenas pulcherrima, and two introduced species of columbid, the Madagascar Turtle-dove, Streptopelia picturata, and the Barred Ground Dove, Geopelia striata, on the Seychelles island of Mahé during September-October 2007. I asked whether: 1) trichomonad infections occur in these species; 2) prevalence varies among species; and 3) birds show any signs of pathogenicity consistent with tricho-monosis. I use the results to assess the potential threat of this pathogen to A. pulcherrima. All three species were infected with trichomonads, and the overall prevalence was 27.5%. Alectroenas pulcherrima had higher prevalence (47.1%) than the two introduced species combined (24.3%). No infected individuals showed any signs of disease. These findings suggest that trichomonad parasites should be considered as a potential disease threat to the A. pulcherrima population.

Prevalence and Pathology of Trichomoniasis in Free – Living Urban Pigeons in the City of Mosul, Iraq

The present study was undertaken to determine the prevalence of trichomoniasis and its pathology in pigeons. A total of 100 free living urban pigeons were collected during the months August and September 2007. The overall prevalence was 16%. In infected pigeons, yellowish – white masses of caseous necrotic material were seen grossly in the oral cavity, esophagus, crop, and proventiculus. Pale to yellow necrotic areas were noted in the liver. Multiple foci of caseous necrosis were seen microscopically in the oral mucosa together with heavy infiltration of inflammatory cells (mainly heterophils). Foci of necrotic inflammation were seen in the liver and there was thickening of the lining mucosa of the esophagus due to extensive infiltration of heterophils. Collections of necrotic material were seen in the mucosa and submucosa of the esophagus. Infection occurred more frequently in young than in adult pigeons. A higher prevalence of the infection was noted in male than in female pigeons. In all of the infected pigeons, trichomoniasis occured in the absence of apparent secondary disease. It was concluded that trichomonad infection is fairly common in free living urban pigeons in the city of Mosul, Iraq.

Documentation of In Vivo and In Vitro Aerobic Resistance of Feline Tritrichomonas foetus Isolates to Ronidazole

The mainstays of treatment for clinically important trichomonad infections are the 5-nitroimidazoles. Metronidazole resistance of feline Tritrichomonas foetus is presumed because of common treatment failure, and tinidazole does not consistently eradicate infection. To date, ronidazole is the only drug demonstrated as effective for treatment of cats infected with T. foetus. To document in vivo treatment failure and identify underlying causes and in vitro conditions of resistance of feline T. foetus to ronidazole. Two intact male Abyssinians failing>or=5 courses of treatment with increasing doses of 5-nitroimidazole drugs. An intact male Abyssinian documented to clear infection after treatment with a single course of ronidazole. T. foetus isolates were cultured from feces and tested in vitro for susceptibility to ronidazole under aerobic and anaerobic culture conditions. A urogenital nidus of T. foetus infection was investigated by culture, polymerase chain reaction, or immunohistochemical testing of urogenital specimens. Resistance to ronidazole under aerobic conditions was uniquely identified in T. foetus isolated from cats with well-documented treatment failure. Treatment failure could not be attributed to reinfection, inappropriate treatment protocol, or presence of a urogenital nidus of infection. Clinical resistance to metronidazole, low efficacy of tinidazole, and present documentation of in vivo and in vitro resistance to ronidazole in some cats are consistent with a high level of cross resistance of feline T. foetus to 5-nitroimidazole drugs. Current lack of alternative drugs with clinical efficacy against feline T. foetus suggests that active investigation of other treatment approaches is warranted.

Studies of trichomonad protozoa in free ranging songbirds: Prevalence of Trichomonas gallinae in house finches ( Carpodacus mexicanus) and corvids and a novel trichomonad in mockingbirds ( Mimus polyglottos)

This study refutes the accepted dogma that significant pathogenic effects of Trichomonas gallinae are limited to columbiformes and raptors in free ranging bird populations in North America. Trichomonads were associated with morbidity and mortality amongst free ranging house finches ( Carpodacus mexicanus), mockingbirds ( Mimus polyglottos) and corvids (scrub jay: Aphelocoma californica; crow: Corvus brachyrhynchos; raven: Corvus corax) in northern California. Prevalence of trichomonad infection was 1.7% in house finches, 0–6.3% in corvids, and 0.9% in mockingbirds. Bird case fatality ratio was 95.5% in house finches, 0–100.0% in corvids, and 37.5% in mockingbirds. DNA sequences of parasites in house finches and corvids were identical to T. gallinae strain g7 (GeneBank AY349182.1) for the 5.8s ribosome. DNA sequences of parasites cultured from two mockingbirds were genetically distinct from that of available sequenced trichomonads. These isolates were clearly phylogenetically more closely related to the Trichomonadinae than the Tritrichomonadinae. While molecular techniques were required to differentiate between trichomonad species, wet mount preparations from the oral cavity/crop were a reliable and inexpensive method of screening for trichomonad infections in these species. Positive wet mount tests in house finches and corvids living in northern California were highly likely to indicate infection with T. gallinae, while in mockingbirds positive wet mounts most likely indicated a trichomonad other than T. gallinae.

Entry and intracellular location of Mycoplasma hominis in Trichomonas vaginalis

The parasite Trichomonas vaginalis causes one of the most common non-viral sexually transmitted infections in humans. The coexistence of different sexually transmitted diseases in the same individual is very common, such as vaginal infections by T. vaginalis in association with Mycoplasma fermentans or Mycoplasma hominis. However, the consequences and behavior of mycoplasma during trichomonad infections are virtually unknown. This study was undertaken to elucidate whether mycoplasmas enter and leave trichomonad cells and if so how. M. hominis was analyzed in different trichomonad isolates and the process of internalization and the pathway within the parasite was studied. Parasites naturally and experimentally infected with mycoplasmas were used and transmission electron microscopy, cytochemistry and PCR analyses were performed. The results show that: (1) M. hominis enters T. vaginalis cells by endocytosis; (2) some mycoplasmas use a terminal polar tip as anchor to the trichomonad plasma membrane; (3) some trichomonad isolates are able to digest mycoplasmas, mainly when the trichomonads are experimentally infected; (4) some fresh virulent isolates are able to maintain mycoplasmas as cohabitants in the cell's interior; (5) some mycoplasmas are able to escape from the vacuole to the trichomonad cytosol, and trichomonad plasma membrane budding suggested that mycoplasmas could leave the parasite cell.

An improved molecular assay for Tritrichomonas foetus

Tritrichomonas foetus ( T. foetus) is the causative agent of bovine trichomonosis, a sexually transmitted disease leading to abortion (from 1 to 8 months gestation), infertility, and occasional pyometra. The annual losses to the U.S. beef industry are estimated to be in the hundreds of millions of dollars. Currently, the “gold standard” diagnostic test for trichomonosis in most countries is the cultivation of live organisms from reproductive secretions. The cultured organisms can then be followed by PCR assays with primers that amplify T. foetus to the exclusion of all other trichomonad species. Thus, negative results present as null data, indistinguishable from failed PCR amplification during T. foetus specific amplification. Our newly developed assay improves previously developed PCR based techniques by using diagnostic size variants from within the internal transcribed spacer 1 (ITS1) region that is between the 18S rRNA and 5.8S rRNA subunits. This new PCR assay amplifies trichomonad DNA from a variety of genera and positively identifies the causative agent in the bovine trichomonad infection. This approach eliminates false negatives found in some current assays as well as identifying the causative agent of trichomonad infection. Additionally, our assay incorporates a fluorescently labeled primer enabling high sensitivity and rapid assessment of the specific trichomonad species. Moreover, electrophoretic separation of amplified samples can be outsourced, thus eliminating the need for diagnostic laboratories to purchase expensive analysis equipment.

Genital and Systemic Immune Responses in a Murine Model of Tritrichomonas foetus Infection

A reliable laboratory animal model would be useful for the study of immune responses to trichomoniasis, a sexually transmitted disease of human beings and cattle. Murine models are available, but pretreatment with estrogen is used, which may influence immune responses. To evaluate whether vaginal trichomoniasis could be established in nonestrogenized mice and to define the immune responses associated with the infection, CD1 and BALB/c mice were studied with or without estrogen treatment prior to inoculation with Tritrichomonas foetus. Tritrichomonas Foetus was cultured from the vagina and uterus of both estrogen-treated and untreated control mice for up to 26 wk. The infection was sustained better in BALB/c than in CD1 mice, suggesting that the former strain was most susceptible. In CD1 mice, infection was sustained less well in estrogen-treated than in untreated control mice, but there was no difference between treatment groups of BALB/c mice. IgA and IgG antibodies in vaginal secretions, uterine secretions, and serum specific for a surface antigen of T. foetus (TF1.17) were measured by enzyme-linked immunosorbent assay. In infected CD1 mice, vaginal IgA and IgG antibodies were detected by 8 wk postinoculation (PI). In infected BALB/c mice, vaginal IgA and IgG antibodies were detected by 12 wk PI. Uterine IgG responses predominated over IgA in estrogen-treated and untreated CD1 and BALB/c mice. There were high levels of IgG, but relatively no IgA in the sera of CD1 and BALB/c mice. Overall, the highest IgA response was in the vaginal secretions of infected CD1 mice, and some animals of this strain cleared the infection. These results show that a chronic trichomonad infection was established in mice without prior treatment with estrogen. The infection was associated with antibody responses in reproductive secretions and serum. This animal model will be useful in studying immunization to protect against trichomoniasis in mice not immunocompromised by estrogen.

Lesions of experimental genital Tritrichomonas foetus infections in estrogenized BALB/c mice.

Ninety-seven BALB/c mice were inoculated intravaginally with 8.0 x 10(5) Tritrichomonas foetus organisms, using either isolate ATCC 30003 or field isolate MU Y22 2 days after estrogenization with 15 micrograms 17 beta-estradiol. Reproductive tracts were examined at several time points post-inoculation to determine gross and histologic responses to trichomonad infection as compared to estrogenized, uninfected control animals. The two isolates varied greatly in ability to maintain chronic infection; no ATCC 30003-inoculated animals remained culture-positive beyond 7 weeks post-inoculation, whereas MU Y22-inoculated animals were infected for greater than 26 weeks. Lesions were seen in 40-60% of animals prior to 10 weeks post-inoculation and included moderate uterine dilation and glandular atrophy, uterine gland abscesses, pyometra, intramural perivascular lymphoid infiltrates, and ovarian bursitis. The severity of lesions was independent of the T. foetus isolate. Lesions became more severe at 10 weeks post-inoculation, and at 10 and 26 weeks post-inoculation, lesions were seen in 60% and 75% of animals, respectively. In addition to lesions described above, epithelial changes were marked at these late necropsies, including ulceration, flattening, hypertrophy, and squamous metaplasia. The lesions seen in these mice closely resemble those described in natural bovine infection, suggesting that the estrogenized BALB/c mouse is an excellent model for study of bovine trichomoniasis.