Tritrichomonas foetus infection in cats with diarrhea from densely housed origins

Molecular-phylogenetic investigation of trichomonads in dogs and cats reveals a novel Tritrichomonas species

BACKGROUND

Trichomonosis is a common infection in small animals, mostly manifesting in gastrointestinal symptoms such as diarrhea. Although oral trichomonads are also known, the species found colonizing the large intestine are more frequently detected protozoa.

METHODS

In the present study, four wildcats, 94 domestic cats, and 25 dogs, originating from 18 different locations in Hungary, were investigated for the presence of oral and large intestinal trichomonads based on the 18S rRNA gene and ITS2.

RESULTS

All oral swabs were negative by polymerase chain reaction (PCR). However, Tritrichomonas foetus was detected in a high proportion among tested domestic cats (13.8%) and dogs (16%), and Pentatrichomonas hominis only in two domestic cats. In addition, a novel Tritrichomonas genotype was identified in one cat, probably representing a new species that was shown to be phylogenetically most closely related to Tritrichomonas casperi described recently from mice. All positive dogs and half of the positive cats showed symptoms, and among cats, the most frequent breed was the Ragdoll.

CONCLUSIONS

With molecular methods, this study evaluated the prevalence of oral and intestinal trichomonads in clinical samples of dogs and cats from Hungary, providing the first evidence of T. foetus in dogs of this region. In contrast to literature data, P. hominis was more prevalent in cats than in dogs. Finally, a hitherto unknown large intestinal Tritrichomonas species (closely related to T. casperi) was shown to be present in a cat, raising two possibilities. First, this novel genotype might have been a rodent-associated pseudoparasite in the relevant cat. Otherwise, the cat was actually infected, thus suggesting the role of a predator-prey link in the evolution of this trichomonad.

Evidence of self-resolution of feline trichomonosis in a pair of single household cats due to ronidazole-resistant Tritrichomonas foetus

Tritrichomonas foetus causes chronic large-bowel diarrhoea in cats, complicated not only by its chronicity but for its difficulty to treat, with few registered or effective products available, subsequently resulting in ronidazole frequently used off-label. The extent of T. foetus resistance to ronidazole is unknown. To demonstrate in vitro resistance of feline T. foetus to ronidazole and the self-resolution of the infection, we isolated novel T. foetus "feline" genotype strains from two cats in 2017 from the same household and monitored these cats over a three-year period. Axenic cultures of T. foetus from the cats were tested for in vitro resistance to metronidazole and ronidazole using anaerobic and aerobic culture assays. The minimum lethal concentration for the novel strains after incubation in aerobic conditions for 48 h were 50-100 μg/ml and 6.25-12.50 μg/ml for metronidazole and ronidazole, respectively. For susceptible T. foetus strains, the minimum lethal concentrations ranged from 1.56-12.50 μg/ml for metronidazole, and 0.39-3.13 μg/ml for ronidazole. The self-resolution of the infection was assessed using repeat diagnostic qPCR and culture. Whilst positive in 2018, the cat samples are no longer returning positive qPCR results in 2020 and 2021, indicating self-resolution over this period. This study demonstrated resistance to ronidazole for the first time in Australian cats and infection self-resolution without antimicrobial intervention is demonstrated. This study provides clinicians with the evidence to reduce the use of off-label ronidazole, and advice on the resolution timeframe for cats in single households.

Tritrichomonas foetus in cats from Central Italy: Clinical signs and risk factors

Tritrichomonas foetus (Trichomonadida, Tritrichomonadidae) is a parasitic protozoan which causes a diarrheic disease in domestic cats worldwide. The epizootiological and pathogenic impact of this parasite in many geographic locations is still to be unraveled; thus, the present study has investigated the occurrence of T. foetus in cats from central Italy, along with the analysis of risk factors and clinical signs. One hundred and five cats referred to the University Veterinary Teaching Hospital of the University of Teramo were tested with copromicroscopic techniques for common intestinal and extra-intestinal parasites and a specific PCR for T. foetus. A statistical analysis evaluating associations between T. foetus positivity and possible risk factors was performed. One animal scored positive for Giardia (0.95%), 2 for Toxocara cati (1.90%), 1 for Eucoleus aerophilus (syn. Capillaria aerophila) (0.95%), 9 for Aelurostrongylus abstrusus (8.57%) and 1 for Dipylididum caninum (0.95%), while T. foetus was molecularly recorded in 18/105 (17.14%) of the study cats. In two cats, T. foetus was found in association respectively with Giardia and A. abstrusus. Animals with chronic gastrointestinal signs were more significantly infected by T. foetus (40.90% vs 10.84%; p < 0.01; 95% CI = 1.90-17.04; OR = 5.69) in comparison to cats with no gastrointestinal distresses. No other statistically significant associations were found. This study confirms that T. foetus is enzootic in cats in Italy and that it should be included in the differential diagnosis of feline chronic gastrointestinal diseases.

Prevalence of Tritrichomonas foetus infection in cats in Bangkok metropolitan area and in vitro drug sensitivity testing

Tritrichomonas foetus is a causative agent of feline trichomonosis, resulting in large-bowel diarrhea in cats. Feline trichomonosis has been reported in the USA, Europe and some Asian countries but there is limited information for Thailand. This study investigated the prevalence of T. foetus infection in cats in the Bangkok metropolitan area and evaluated the in vitro efficacy of metronidazole (MDZ) and ronidazole (RDZ) against T. foetus Thai isolates. In total, 215 fecal samples were collected from 121 owned cats and 94 stray cats. All fecal samples were cultivated in InPouch™ TF-feline medium. Afterward, polymerase chain reaction (PCR) assays targeting the 5.8S rRNA gene, the ITS regions and DNA sequencing were used for the confirmation of T. foetus. The overall prevalence of T. foetus infection was 4.18% (9/215) based on cultivation and PCR. The sequencing results showed 100% homology to T. foetus sequences from GenBank. The average minimal lethal concentrations (MLCs) of MDZ were 333.33 and 66.67 μg/ml at 24 and 48 h, respectively. The average MLCs of RDZ were 29.16 and 12.5 μg/ml at 24 and 48 h, respectively. The MLC of the MDZ results revealed that T. foetus Thai isolates had a tendency to be MDZ-resistant. To the best of the authors' knowledge, this study was the first using in vitro cultivation and molecular techniques to report and confirm the presence of T. foetus in cats living in the Bangkok metropolitan area. Further studies are needed to determine the genuine infection rate of T. foetus in a greater population sample and the infection status in cats with signs of diarrhea in Thailand.

Nguyen D, A. Phan T, M. Hamada S, Panchel R, C. Tam C, H. Kim J, W. Cheng L, M. Land K. The Inhibitory Activity of Anthraquinones against Pathogenic Protozoa, Bacteria, and Fungi and the Relationship to Structure

Plant-derived anthraquinones were evaluated in cell assays for their inhibitory activities against the parasitic protozoa Trichomonas vaginalis human strain G3 that causes the sexually transmitted disease trichomoniasis in women, Tritrichomonas foetus bovine strain D1 that causes sexually transmitted diseases in farm animals (bulls, cows, and pigs), Tritrichomonas foetus-like strain C1 that causes diarrhea in domestic animals (cats and dogs), and bacteria and fungi. The anthraquinones assessed for their inhibitory activity were anthraquinone, aloe-emodin (1,8-dihydroxy-3-hydroxymethylanthraquinone), anthrarufin (1,5-dihydroxyanthraquinone), chrysazin (1,8-dihydroxyanthraquinone), emodin (1,3,8-trihydroxy-6-methylanthraquinone), purpurin (1,2,4-trihydroxyanthraquinone), and rhein (1,8-dihydroxy-3-carboxyanthraquinone). Their activities were determined in terms of IC₅₀ values, defined as the concentration that inhibits 50% of the cells under the test conditions and calculated from linear dose response plots for the parasitic protozoa, and zone of inhibition for bacteria and fungi, respectively. The results show that the different substituents on the anthraquinone ring seem to influence the relative potency. Analysis of the structure–activity relationships in protozoa indicates that the aloe-emodin and chrysazin with the highest biological activities merit further study for their potential to help treat the diseases in women and domestic and farm animals. Emodin also exhibited antifungal activity against Candida albicans. The suggested mechanism of action and the additional reported beneficial biological properties of anthraquinones suggest that they have the potential to ameliorate a broad spectrum of human diseases.

Tritrichomonas Foetus: A Study of Prevalence in Animal Hosts in Poland

Tritrichomonas foetus is described as a pathogen of cattle and cats and also exhibits commensalism with pigs. In order to estimate the prevalence and determine the risk factors for parasite infection, specimens from animal hosts (cat, pigs, and cattle) from Poland were investigated. To our best knowledge, this is the first such study to examine samples from wild boars (Sus scrofa) for the presence of T. foetus. Data were collected from 117 cats, 172 pigs, 236 wild boars, and 180 cattle. The sensitivity of T. foetus identification was increased by using two molecular assays: PCR and loop-mediated isothermal amplification (LAMP). The prevalence of feline tritrichomonosis was 20.51%, and statistically significant differences were obtained between groups of animals regarding age, breed, number of cats, diarrhea, and place of living. Positive PCR and LAMP results for T. foetus were estimated for 16.28% of pigs, and the obtained data were significantly correlated with age. Conversely, no significant differences were observed concerning the farm size factor. In our survey, no cases of bovine tritrichomonosis were found, which is consistent with the data from the other countries of the European Union. Similarly, all wild boar samples were also T. foetus-negative according to LAMP and PCR.

Association of fecal sample collection technique and treatment history with Tritrichomonas foetus polymerase chain reaction test results in 1717 cats

BACKGROUND

Fecal polymerase chain reaction (PCR) testing for Tritrichomonas foetus is considered the most sensitive means for diagnosis of infection but results could be influenced by fecal collection technique and prior use of antimicrobial drugs.

OBJECTIVES

To establish any association between fecal collection technique or treatment history and results of fecal PCR testing for T. foetus.

ANIMALS

Fecal samples from 1717 cats submitted by veterinarians between January 2012 and December 2017.

METHODS

This study used a retrospective analysis. T. foetus PCR test results from 1808 fecal samples submitted for diagnostic testing were examined for their association with method of fecal collection and prior antimicrobial treatments. Data were collected from sample submission form.

RESULTS

Positive T. foetus PCR test results were obtained for 274 (16%) cats. Fecal samples collected via fecal loop had increased probability of positive PCR test results (odds ratio [OR] 2.04, 95% confidence interval [CI] 1.31-3.17, P = .002) compared to samples collected by colonic flush. There was no association between PCR test results and treatment history, treatment type, or prior treatment with ronidazole. After an initial positive PCR test, 4/19 (21%; 95% CI 2.7%-39.4%) cats treated with ronidazole had a second positive test result.

CONCLUSIONS AND CLINICAL IMPORTANCE

Results of this study support that fecal samples collected by loop might be better for PCR diagnosis of T. foetus infection. Lack of association of ronidazole with PCR test results and a 21% all-potential-causes failure rate of ronidazole in cats with preconfirmed infection are important limitations to use of this drug.

Multilocus analysis reveals further genetic differences between Tritrichomonas foetus from cats and cattle

Tritrichomonas foetus isolates from feline and bovine origin has been previously shown to carry a certain degree of genetic heterogeneity. Here, novel candidate molecular markers were developed by means of multilocus sequence typing of the gap2 gene (encoding for T. foetus glyceraldehyde-3-phosphate dehydrogenase), ITS region, the TR7/TR8 variable-length repeat and microsatellite genotyping. These markers were used to characterize T. foetus field isolates from bulls and domestic cats and to compare phylogenetically with the following ATCC isolates: T. foetus isolated from cattle and pig (syn. Tritrichomonas suis), Tritrichomonas mobilensis, Tetratrichomonas gallinarum and Pentatrichomonas hominis. Among them, TFMS10 and TFMS7 were found to be the most polymorphic markers. Moreover, an 809 bp fragment of the gap2 gene was successfully amplified from all the trichomonads included in this study and the sequence analysis revealed differences between T. foetus porcine and feline genotypes and T. mobilensis in comparison to the bovine T. foetus ATCC isolate. The TR7/TR8 repeat pattern was not reproducible, being only consistent the fragments of approximately 110 and 217 bp. Sequence analysis of the latter revealed the existence of 3 SNPs resulting in 98.6 % homology between bovine and feline isolates. A search for similar sequences was carried out to develop a Restriction Length Fragment Polymorphism analysis. A 503 bp region, named TF1, revealed the existence of two BbvI restriction enzyme sites that were able to generate different length fragments for T. foetus feline and bovine isolates. Finally, the neighbour-joining analyses showed that T. foetus porcine genotype clusters together with bovine genotype, whereas T. mobilensis and the feline genotype form a separate cluster.

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.

Prevalence of enteropathogens in cats with and without diarrhea in four different management models for unowned cats in the southeast United States

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Most cats in shelters, sanctuaries, foster homes, and trap-neuter-return programs carried at least one enteropathogen.

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Tritrichomonas foetus and coronavirus were more common in cats with diarrhea.

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Other bacterial, viral, protozoal, and helminth enteropathogens were present in cats with normal feces and diarrhea.

The objective of this study was to determine the prevalence of enteropathogens in cats with and without diarrhea in four different models for managing unowned cats: short-term animal shelter, long-term sanctuary, home-based foster care, and trap-neuter-return. Fecal samples from 482 cats, approximately half of the cats with normal fecal consistency and half with diarrhea, were tested by zinc sulfate centrifugation and by real-time PCR for a panel of enteropathogens.

At least one enteropathogen of feline or zoonotic importance was detected in a majority of cats, regardless of management model. For most enteropathogens, the presence or absence of diarrhea was not significantly associated with infection, the exceptions being Tritrichomonas foetus in sanctuary cats with diarrhea (26%) and normal fecal consistency (10%), respectively (P ≤ 0.04), and feline coronavirus in foster cats (80% and 58%) (P ≤ 0.001). The types of enteropathogens detected were related to the type of management model, e.g., viral and protozoal infections were most common in shelters, sanctuaries, and foster homes (confinement systems), whereas helminth infections were most common in trap-neuter-return programs (free-roaming cats).

These results suggest that management practices for unowned cats are inadequate for control of enteropathogens and that the presence of diarrhea is a poor indicator of enteropathogen carriage. Risk-management strategies to reduce transmission to people and other animals should focus on sanitation, housing, compliance with preventive care guidelines, periodic surveillance, response to specific enteropathogens, humane population management of free-roaming community cats, public health education, and minimizing the duration and number of cats in mass confinement.

Trichomonas

The most widely known trichomonad in veterinary medicine is Tritrichomonas foetus. It is the etiologic agent of bovine tritrichomonosis, a sexually transmitted disease in extensively managed herds throughout many geographic regions worldwide. The same trichomonad species is also regarded as the causative agent of chronic diarrhea in the domestic cat, although more recent studies observed molecular differences between bovine- and feline-derived T. foetus. Trichomonosis in cats has a worldwide distribution and is mainly present among cats from high-density housing environments. Other trichomonads are found as inhabitants of the gastrointestinal tract in birds, such as Trichomonas gallinae. Particularly, Columbiformes, Falconiformes, Strigiformes, and wild Passeriformes can be severely affected by avian trichomonads. Diagnosis of trichomonosis is often complicated by the fragility of the parasite. To ensure valid test results, it is essential to collect and handle specimens in the right way prior to analysis. Cultivation tests, the specific amplification of parasites, or a combination of both test methods is the most efficient and most commonly used way to diagnose trichomonosis in animals. Bovine tritrichomonosis is mainly controlled by the identification and withdrawal of infected animals from bovine herds. The control of feline and avian trichomonosis relies mainly on preventive measures.

Draft Genome Sequence of Tritrichomonas foetus Strain K

The protist Tritrichomonas foetus (Excavata, Parabasalia) is a parasite that causes bovine and feline trichomonosis. Bovine trichomonosis is a venereal disease that leads to abortion and reproductive problems in herds. Feline trichomonosis affects domestic cats. Here, we report the genome sequence of the T. foetus K strain, isolated in Brazil.

The conundrum of feline Trichomonosis

Practical relevance: Trichomonosis of the large intestine of the cat was described as a cause of chronic diarrhea over 20 years ago. The trichomonad was identified as Tritrichomonas foetus, with a genotype that is distinct from venereal T foetus of cattle. Clinical challenges: Despite multiple means for diagnosis of the infection, including light microscopy, protozoal culture and PCR amplification using species-specific primers, tests with even greater sensitivity are needed. Feline trichomonosis is resistant to all commonly used antiprotozoal drugs. Ronidazole is currently the only drug demonstrated to be effective in eliminating the infection from cats; however, this drug has a narrow safety margin and clinical resistance is increasingly recognized. The more we learn about trichomonosis in cats, the more complicated and controversial the infection has become, ranging from what we should call the organism to whether we should even bother trying to treat it. Global importance: Feline trichomonosis is recognized to occur worldwide and is regarded as one of the most common infectious causes of colitis in the domestic cat. The infection is widespread in catteries and shelters; and, while remission of diarrhea may occur over time, persistence of the infection is common. Evidence base: This review provides a comprehensive examination of what is currently known about feline trichomonosis and pinpoints areas, based on the authors' opinion, where further research is needed.

Novel genotype of Tritrichomonas foetus from cattle in Southern Africa

Bovine trichomonosis caused by Tritrichomonas foetus is a significant reproductive disease of cattle. Preputial samples were collected using sheath washing technique in bulls in Namibia. Thirty-six trichomonad cultures were characterized using the TaqMan-probe commercial real-time polymerase chain reaction (PCR) diagnostic assay (VetMAX™-Gold Trich Detection Kit) and CYBR real-time PCR assay based on TFR3/4 primers. Diagnostic real-time PCRs and DNA sequencing of the internal transcribed region confirmed presence of T. foetus in 35 out of 36 samples. Multilocus genotyping using cysteine proteases (CP1, CP2, CP4, CP5, CP6, CP7, CP8, CP9) and malate dehydrogenase (MDH1) gene sequences demonstrate that the T. foetus in Namibia are genetically distinct from those characterized elsewhere. We report the discovery of a novel genotype of T. foetus in Namibian cattle, distinct from other T. foetus genotypes in Europe, South and North America and Australia. We suggest recognition of a 'Southern African' genotype of T. foetus. Identification of the new genotype of T. foetus demonstrates the need for wider global sampling to fully understand the diversity and origin of T. foetus causing disease in cattle or cats.