Chronic diarrhoea associated with Tritrichomonas foetus infection in a British cat

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.

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.

Cross-sectional survey on Tritrichomonas foetus infection in Italian cats

The feline genotype of Tritrichomonas foetus is a widespread cause of large-bowel diarrhoea in cats. The aim of this study was to determine the prevalence of the T. foetus infection in cat populations across Italy. Fresh, individual faecal samples were collected from 267 cats, kept in different environments (i.e., private households, breeding structures, municipal catteries and colonies) in three different sites across Italy. The faecal samples were tested by PCR to detect T. foetus. Moreover, the same samples were subjected to a concentration-flotation technique and a commercial direct fluorescent-antibody (DFA) test to detect additional enteric parasites, including Giardia duodenalis. The overall prevalence of T. foetus infection was 5.2%. All the infected cats showed diarrhoea at the time of sampling: 9 out of 14 positive cats were co-infected with G. duodenalis, 1 with Toxocara cati and 3 with Dipylidium caninum. The risk factor analysis showed that not only the breed, but also co-infections with G. duodenalis and Dipylidium caninum were significantly associated with the presence of T. foetus. This study confirms the presence of T. foetus in cats living in Italy, suggesting that this protozoan parasite should always be included in the differential diagnosis of patients referred with large-bowel disease symptoms, especially if they were purebred animals, or affected by other enteric protozoa, such as G. duodenalis.

Trichomonosis in cats with diarrhoea in Hong Kong, China, between 2009 and 2014

Case series summary

Infection of the domestic cat by Tritrichomonas blagburni, previously referred to as T foetus, may lead to a disease called feline trichomonosis, which manifests clinically as large bowel diarrhoea. The disease has a wide geographical distribution, including numerous countries in Europe, North America and Australia/Oceania. Nevertheless, it has occasionally been reported in Asia, South Korea and Japan. A retrospective study was carried out to include all domestic cats with diarrhoea, presented to two veterinary clinics in Hong Kong, China, between 1 July 2009 and 30 June 2014. A total of 29 cats with diarrhoea were diagnosed with Tritrichomonas species infection by means of quantitative PCR and direct microscopy. Tritrichomonas species was more frequently found in young (median age 10 months), male (66%) and purebred cats (86%). Giardia species was found in 31% of Tritrichomonas species-positive cats. The recommended dose of ronidazole (30 mg/kg q24h for 14 days) resolved clinical signs in 83% of diagnosed cats.

Relevance and novel information

This case series describes Tritrichomonas species as a cause for feline chronic diarrhoea in cats in China. The high rate of failure (17%) in those cats receiving a standard regimen of ronidazole might be due to owner or patient compliance rather than protozoal resistance to the drug.

Tritrichomonas foetus infection, a cause of chronic diarrhea in the domestic cat

Tritrichomonas foetus is a very intriguing trichomonad protozoan with respect to its varied choice of residence in the different host species. It is an obligate parasite of the reproductive and the gastrointestinal tract of bovine and feline host respectively, leading to trichomonosis. Bovine trichomonosis is a sexually transmitted disease whereas feline trichomonosis is a disease with a purported fecal-oral route of spread. Further, the trichomonad is a commensal in the nasal passages, stomach, cecum and colon of swine host. Advances have been exponential in understanding the trichomonad biology and specifically feline trichomonosis since late 1990s and early 2000s when T. foetus was soundly determined to be a causative agent of chronic diarrhea in the domestic cat. It is a challenging task, even for a skilled investigator not to mention the busy clinical veterinarian, to keep up with the vast volume of information. Here we comprehensively reviewed the trichomonad biology, clinical manifestations, pathogenesis, host immunity, world map of distribution, risk factors, diagnosis and treatment. Risk factors associated with T. foetus-positive status in the domestic cat include young age, purebred, history of diarrhea, co-infections with other enteral pathogens. In addition, molecular similarity of bovine and feline isolates of T. foetus in DNA sequence was concisely discussed. The data presented serve as an information source for veterinarians, and investigators who are interested in biology of T. foetus and feline trichomonosis.

A retrospective molecular study of select intestinal protozoa in healthy pet cats from Italy

The feline gut can harbour a number of protozoan parasites. Recent genetic studies have highlighted new epidemiological findings about species of Cryptosporidium, assemblages of Giardia duodenalis and Toxoplasma gondii. Furthermore, epidemiological studies suggest the occurrence of Tritrichomonas foetus in cats is on the increase worldwide. The prevalence of selected intestinal protozoa was determined by PCR using DNA previously extracted from the faeces of 146 privately owned healthy cats from Italy. Molecular genotyping on T gondii, G duodenalis and Cryptosporidium DNA was achieved. PCR assays were positive in 32 (22.9%) samples. Three animals (2.0%) were positive for T foetus and Cryptosporidium DNA, 15 specimens (10.3%) were positive for T gondii and 11 (7.5%) for G duodenalis. Co-infections were never observed. Results of the typing analysis allowed the identification of Cryptosporidium felis in all cases. The specimens positive for T gondii hinted at clonal genotype I (n = 7), genotype II (n = 1) and genotype III (n = 7). The G duodenalis isolates were referable to assemblages F (n = 9) and C (n = 2). In conclusion, the results obtained in this study add to the literature regarding the epidemiology of these parasites by confirming their presence in the faeces of healthy pet cats.

Tritrichomoniasis in cats: ABCD guidelines on prevention and management

OVERVIEW

Tritrichomonas foetus is a protozoan organism that is specific to cats and can cause large bowel diarrhoea. It is distinct from other Tritrichomonas species and not considered to be zoonotic. Infection is most common in young cats from multicat households, particularly pedigree breeding catteries.

DISEASE SIGNS

Affected cats show frequent fetid diarrhoea, often with mucus, fresh blood and straining, but generally remain bright and do not lose weight.

DIAGNOSIS

Diagnosis of infection is usually based on direct microscopic examination of freshly voided faeces. Polymerase chain reaction (PCR) testing is more sensitive but may detect infections unrelated to diarrhoea and, therefore, requires care in interpretation.

TREATMENT

The treatment of choice is ronidazole, which should be used with care as it is an unlicensed drug for cats with a narrow safety margin. Clinical signs are generally self-limiting in untreated cases, but may take months to resolve.

Detection of Tritrichomonas foetus and Pentatrichomonas hominis in intestinal tissue specimens of cats by chromogenic in situ hybridization

In this retrospective study 102 cats were analyzed for the presence of trichomonads in intestinal tissue sections using chromogenic in situ hybridization (CISH). Two intestinal trichomonad species are described in cats: Pentatrichomonas hominis and Tritrichomonas foetus. While P. hominis is considered a mere commensal, T. foetus has been found to be the causative agent of feline large-bowel diarrhea. For the detection of both agents within intestinal tissue CISH assays using three different probes were performed. In the first CISH run a probe specific for all relevant members of the order Trichomonadida (OT probe) was used. In a second CISH run all positive samples were further examined on three consecutive tissue sections using the OT probe, a probe specific for the family of Tritrichomonadidae (Tritri probe) and a newly designed probe specifically detecting P. hominis (Penta hom probe). In total, four of the 102 cats were found to be positive with the OT probe. Thereof, one cat gave a positive reaction with the P. hominis probe and three cats were positive with the T. foetus probe. All Trichomonas-positive cats were pure-bred and between 8 and 32 weeks of age. In one cat positive for T. foetus large amounts of parasites were found in the gut lumen and invading the intestinal mucosa. The species of the detected trichomonads were confirmed by polymerase chain reaction and nucleotide sequencing of a part of the 18S ribosomal RNA gene. In this study, the usefulness of CISH to detect intestinal trichomonads within feline tissue samples was shown. Additionally, the specific detection of P. hominis using CISH was established. Generally, it was shown that CISH is well suited for detection and differentiation of trichomonosis in retrospective studies using tissue samples.

A cross-sectional study of Tritrichomonas foetus infection among healthy cats at shows in Norway

Background

In recent years, the protozoan Tritrichomonas foetus has been recognised as an important cause of chronic large-bowel diarrhoea in purebred cats in many countries, including Norway. The aim of this cross-sectional study was to determine the proportion of animals with T. foetus infection among clinically healthy cats in Norway and to assess different risk factors for T. foetus infection, such as age, sex, former history of gastrointestinal symptoms and concurrent infections with Giardia duodenalis and Cryptosporidium sp.

Methods

The sample population consisted of 52 cats participating in three cat shows in Norway in 2009. Samples were examined for motile T. foetus by microscopy, after culturing and for T. foetus-DNA by species-specific nested PCR, as well as for Giardia cysts and Cryptosporidium oocysts by immunofluorescent antibody test (IFAT).

Results

By PCR, T. foetus-DNA was demonstrated in the faeces of 11 (21%) of the 52 cats tested. DNA-sequencing of five positive samples yielded 100% identity with previous isolates of T. foetus from cats. Only one sample was positive for T. foetus by microscopy. By IFAT, four samples were positive for Giardia cysts and one for Cryptosporidium oocysts, none of which was co-infected with T. foetus. No significant associations were found between the presence of T. foetus and the various risk factors examined.

Conclusions

T. foetus was found to be a common parasite in clinically healthy cats in Norway.

First description of naturally acquired Tritrichomonas foetus infection in a Persian cattery in Spain

Tritrichomonas foetus has been identified as the causative agent of feline intestinal trichomonosis, characterized by clinical signs of chronic large bowel diarrhoea. This disease has been reported in cats from the USA, Europe and Australia. However, its epidemiology is still unclear. The aim of the present study was to describe T. foetus infection in a Persian cattery in Spain. T. foetus infection was sequentially diagnosed in 20 cats by direct faecal smear examined under the microscope, specific culture (In Pouch TF medium) and PCR. A standard coprological sedimentation method was also performed in order to screen for other intestinal parasites in all the cats included. In addition, sera were tested for IgG antibodies against Leishmania infantum, Toxoplasma gondii, and for the detection of feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV). Five out of 20 cats were positive for T. foetus (25%), two of them by microscopy, culture and PCR and three by culture and PCR. No association was found between T. foetus infection and age or sex. L. infantum and T. gondii seroprevalence rates were 15% and 10%, respectively. The prevalence of FeLV p27 antigen and of FIV antibodies in the study population was zero. Cystoisospora spp. oocysts were detected in one cat. These preliminary results show that the transmission of T. foetus infection in cluster conditions may occur between asymptomatic cats and young or immunocompromised animals.

Tritrichomonas foetus infection in purebred cats in Germany: prevalence of clinical signs and the role of co-infection with other enteroparasites

The aim of this study was to determine the prevalence of Tritrichomonas foetus infection and associated clinical signs in purebred cats in Germany, to investigate the role of co-infection, and identify determinants of infection. Faecal specimens accompanied by epidemiological questionnaires were scored and collected from 230 purebred cats. Faeces were examined for trichomonads and other enteroparasites. The prevalence of T foetus was 15.7% among cats and 18.5% among catteries. An abnormal faecal score and history of diarrhoea were observed in 64% and 61% of T foetus-positive cats, respectively, and correlated significantly with infection. Co-infection, observed in 36% of T foetus-infected cats, was not associated with diarrhoea. Norwegian Forest cats were infected significantly more often than other breeds. No association was found with any environmental factors. This study demonstrated a high prevalence of symptomatic T foetus infections in purebred cats in Germany. Co-infection with other enteroparasites did not worsen clinical signs of trichomonosis.

Naturally occurring Tritrichomonas foetus infections in Australian cats: 38 cases

A total of 38 cases of naturally occurring intestinal tritrichomoniasis in Australian cats are described. Detailed information was available for 13 cases diagnosed in two veterinary hospitals, one in Victoria and one in New South Wales (NSW). In all instances, presumptive microscopic diagnoses were confirmed by polymerase chain reaction (PCR) testing. Affected cats were generally young (median age 8 months) and of a pedigree breed (12/13 cats; 92%). Diarrhoea was observed in 10 cats (77%); the remaining three cats were asymptomatic and detected by screening undertaken because these cats cohabited with symptomatic cases. Concurrent infections with Giardia species (7/13 cats; 54%), and Toxocara species and Eucoleus species (2/13 cats; 15%) were identified. Treatment of tritrichomoniasis with ronidazole at a dose of 30mg/kg once or twice a day, in concert with appropriate therapy of concurrent gastrointestinal infections, resolved diarrhoea in all cats treated. Limited case details of a further 25 infected cats were obtained from a commercial laboratory offering a real-time PCR assay for Tritrichomonas foetus, and compared with findings from the 13 cats presenting to the contributing veterinary hospitals. All samples submitted to this laboratory returning a positive PCR result were from pedigree cats maintained in multi-cat facilities. Most of the samples were derived from Victoria (4/8 catteries tested; 50%), although positive samples were also identified from cats in NSW (1/4 catteries tested; 25%), Queensland (1/4 catteries; 25%), Tasmania (1/4 catteries; 25%) and South Australia (1/4 catteries; 25%). Our impression is that intestinal tritrichomoniasis is an emerging infectious disease of Australian cats. Tests to detect T foetus should be a routine component of the work-up of chronic diarrhoea in cats, especially young purebred cats.

Tritrichomonas foetus infection in cats with diarrhoea in a rescue colony in Italy

Faecal samples from 74 cats with chronic large bowel diarrhoea that were living in a rescue colony in Italy, were submitted for assessment of Tritrichomonas foetus by direct microscopy of faecal smears (n=20) and T foetus-specific culture (n=74), with confirmation by polymerase chain reaction (n=1). Twenty-four of the cats (32%) were found to be infected with T foetus. The infected cats were predominantly over a year of age (67%) and were all neutered non-pedigree domestic cats.

Feline diarrhoea associated with Tritrichomonas cf. foetus and Giardia co-infection in an Australian cattery

A 10-week-old female Ocicat was presented at a primary care feline veterinary practice for failure to thrive and diarrhoea. Numerous trophozoites, atypical for Giardia sp., were detected on a direct faecal examination, in addition to Giardia cysts. Although the failure to thrive and diarrhoea resolved following treatment for giardiasis, further diagnostic tests performed on faecal specimens from the kitten and 15 other Ocicats from the same cattery, including culture of trophozoites in In Pouch medium, PCR testing and molecular sequencing of PCR amplicons, confirmed infection with Tritrichomonas cf. foetus. This is the first report in Australia of feline trichomoniasis, which appears to be an emerging infectious disease of cats. Pertinent information regarding the clinical features, diagnosis, therapy, and potential source of feline trichomoniasis within Australia are discussed.

Intestinal Tritrichomonas foetus infection in cats in Switzerland detected by in vitro cultivation and PCR

Tritrichomonas foetus, a parasite well known for its significance as venereally transmitted pathogen in cattle, has recently been identified as a cause of chronic large-bowel diarrhea in domestic cats in the US, UK, and, more recently, also in Norway. In a period of 3 months (October to December 2007), 45 cats of Switzerland suffering from chronic diarrhea were investigated for intestinal infections, including a search for trichomonads. A commercially available in vitro culture system was used to screen for infection, complemented with a PCR and subsequent amplicon sequencing to support speciation. The PCR is based upon amplification of a sequence derived from the internal transcribed spacer region 1 (ITS1) on the ribosomal RNA gene (rRNA) using primers designed to detect a broad range of genera and species belonging to the family of Trichomonadidae. The method was furthermore adapted to the uracil DNA glycosylase (UDG) system in order to prevent carry-over contamination and it included a recombinant internal control to track for inhibitory reactions. Eleven out of the 45 cats were culture-positive, as revealed by microscopic identification of trichomonadid organisms. One of the isolates was subjected to scanning electron microscopy and findings revealed the presence of three flagella, thus placing the isolate into the gender Tritrichomonas sp. PCR and subsequent amplicon sequencing were carried out with ten of the 11 isolates. A total homology with published T. foetus sequences was confirmed in all of the cases. T. foetus therefore appears to range among those organisms that can cause chronic diarrhea in cats in Switzerland.

Prevalence of Tritrichomonas foetus infection in cats with diarrhoea in the UK

Faecal samples from 111 cats with diarrhoea that were living in the UK were submitted for the assessment of Tritrichomonas foetus infection by polymerase chain reaction (PCR). Sixteen (14.4%) samples were found to be positive. In agreement with studies from the USA, infected cats were predominantly of a year of age or less and of a pedigree breed, with Siamese and Bengal cats specifically over-represented in this population.