Tritrichomonas foetus Infection in Cats

Gookin JL, Stauffer SH, Dybas D et al: Documentation of In Vivo and In Vitro Aerobic Resistance of Feline Tritrichomonas foetus Isolates to Ronidazole, J Vet Intern Med 24:1003, 2010.


One cause of chronic large bowel diarrhea in cats is a protozoal pathogen called Tritrichomonas foetus. Estimates indicate that up to 30% of purebred show cats and 29% of cats with clinical signs of infection are infected with this organism in the United States. Trichomonads like T. foetus are susceptible to the effects of 5-nitroimidazole drugs because they utilize reductive metabolic pathways. Ronidazole is the only drug demonstrated as effective for treatment of cats infected with T. foetus and resistance to ronidazole has not been reported previously. In this study, two intact male Abyssinian cats with T. foetus were found to have resistance to increasing dosages of ronidazole. Treatment with multiple courses of metronidazole and tinidazole also did not eradicate the infection. The true prevalence of treatment resistance in the infected cat population is not known. A persistent infection in treated cats should be confirmed by the results of follow-up testing rather than assumed on the basis of clinical signs. Cats should be isolated from sources of re-infection. Cross-resistance among 5-nitroimidazole drugs has been described and the current lack of alternative drugs that have clinical efficacy against feline T. foetus suggests the need for an active investigation of other treatment approaches. [VT]

Related articles:
Payne PA, Artzer M: The biology and control of Giardia spp and Tritrichomonas foetus, Vet Clin North Am Small Anim Pract 39:993, 2009.

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Gookin JL, Stauffer SH, Dybas D et al: Documentation of In Vivo and In Vitro Aerobic Resistance of Feline Tritrichomonas foetus Isolates to Ronidazole, J Vet Intern Med 24:1003, 2010.


One cause of chronic large bowel diarrhea in cats is a protozoal pathogen called Tritrichomonas foetus. Estimates indicate that up to 30% of purebred show cats and 29% of cats with clinical signs of infection are infected with this organism in the United States. Trichomonads like T. foetus are susceptible to the effects of 5-nitroimidazole drugs because they utilize reductive metabolic pathways. Ronidazole is the only drug demonstrated as effective for treatment of cats infected with T. foetus and resistance to ronidazole has not been reported previously. In this study, two intact male Abyssinian cats with T. foetus were found to have resistance to increasing dosages of ronidazole. Treatment with multiple courses of metronidazole and tinidazole also did not eradicate the infection. The true prevalence of treatment resistance in the infected cat population is not known. A persistent infection in treated cats should be confirmed by the results of follow-up testing rather than assumed on the basis of clinical signs. Cats should be isolated from sources of re-infection. Cross-resistance among 5-nitroimidazole drugs has been described and the current lack of alternative drugs that have clinical efficacy against feline T. foetus suggests the need for an active investigation of other treatment approaches. [VT]

Related articles:
Payne PA, Artzer M: The biology and control of Giardia spp and Tritrichomonas foetus, Vet Clin North Am Small Anim Pract 39:993, 2009.

More on cat health: Winn Feline Foundation Library
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Tritrichomonas and Reproductive Disease in Cats

Winn-funded research

Gray S, Hunter S, Stone M, Gookin J. Assessment of reproductive tract disease in cats at risk for Tritrichomonas foetus infection. Am J Vet Res. 2010;71(1):76-81.

Tritrichomonas foetus is a venereal pathogen of cattle. Since 2003, T. foetus has been identified in cats as a pathogen of the gastrointestinal tract. In cats, T. foetus resides in epithelial secretions and crypts of the colon. The infection is common in purebred cats. This study’s objective was to determine whether T. foetus infection resides in reproductive tract tissues from cats housed for breeding and where a high prevalence of colonic T. foetus infection has been reported. Sixty-one purebred cats in 36 catteries had reproductive tract tissue, feces, and a reproductive history evaluated. Tissues were examined for T. foetus via light microscopy, immunohistochemical analysis, and PCR assay. Fifteen of 61 cats (25%) and 22 of 33 (67%) catteries were identified with active or reported T. foetus infection. T. foetus infection of the reproductive tract was not detected in any cats. There were also no differences in total number of litters, number of litters per breeding, kitten mortality rate, or birth defects between cats or catteries infected with T. foetus and those for which T. foetus infection was not identified. The authors concluded there was no evidence of reproductive tract colonization by T. foetus found in this study. Therefore, it is unlikely that reproductive tract infection with T. foetus plays an important role in overall disease transmission. [VT]

Related articles:
Tolbert MK, Gookin J. Tritrichomonas foetus: a new agent of feline diarrhea. Compend Contin Educ Vet. 2009;31(8):374-381.

Payne PA, Artzer M. The biology and control of Giardia spp and Tritrichomonas foetus. Vet Clin North Am Small Anim Pract. Nov 2009;39(6):993-1007, v.

More on cat health: Winn Feline Foundation Library
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Winn-funded research

Gray S, Hunter S, Stone M, Gookin J. Assessment of reproductive tract disease in cats at risk for Tritrichomonas foetus infection. Am J Vet Res. 2010;71(1):76-81.

Tritrichomonas foetus is a venereal pathogen of cattle. Since 2003, T. foetus has been identified in cats as a pathogen of the gastrointestinal tract. In cats, T. foetus resides in epithelial secretions and crypts of the colon. The infection is common in purebred cats. This study’s objective was to determine whether T. foetus infection resides in reproductive tract tissues from cats housed for breeding and where a high prevalence of colonic T. foetus infection has been reported. Sixty-one purebred cats in 36 catteries had reproductive tract tissue, feces, and a reproductive history evaluated. Tissues were examined for T. foetus via light microscopy, immunohistochemical analysis, and PCR assay. Fifteen of 61 cats (25%) and 22 of 33 (67%) catteries were identified with active or reported T. foetus infection. T. foetus infection of the reproductive tract was not detected in any cats. There were also no differences in total number of litters, number of litters per breeding, kitten mortality rate, or birth defects between cats or catteries infected with T. foetus and those for which T. foetus infection was not identified. The authors concluded there was no evidence of reproductive tract colonization by T. foetus found in this study. Therefore, it is unlikely that reproductive tract infection with T. foetus plays an important role in overall disease transmission. [VT]

Related articles:
Tolbert MK, Gookin J. Tritrichomonas foetus: a new agent of feline diarrhea. Compend Contin Educ Vet. 2009;31(8):374-381.

Payne PA, Artzer M. The biology and control of Giardia spp and Tritrichomonas foetus. Vet Clin North Am Small Anim Pract. Nov 2009;39(6):993-1007, v.

More on cat health: Winn Feline Foundation Library
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Stability of Tritrichomonas foetus

Hale S, Norris JM, Slapeta J: Prolonged resilience of Tritrichomonas foetus in cat faeces at ambient temperature, Vet Parasitol 166:60, 2009.

This study, from the University of Sydney, Australia, was designed to investigate two culture methods for Tritrichomonas foetus, and to evaluate the effect of sample storage time on diagnostic utility. The two culture methods evaluated were InPouch TF-Feline (Bio-Med Diagnostics) and Modified Diamond's Medium. Two batches of normal cat feces were spiked with T. foetus prior to being stored either at room temperature or refrigerated. At different time points, small samples were taken from the original batches and tested in the culture systems. Both culture systems performed well. The accumulative sensitivity was found to be 83% and 100% for the InPouch TF-Feline and Modified Diamond's Medium respectively over a 6 hour period. The researchers were able to successfully culture T. foetus from feces that had been stored at room temperature for 24 hours. This finding may indicate that the environmental resilience of the organism may be more robust than previously thought, and that transmission may not be limited to close contact between cats. [SL]
>> PubMed Abstract

Related articles:
Tolbert MK, Gookin J: Tritrichomonas foetus: A New Agent of Feline Diarrhea, Compend Contin Educ Vet 31:374, 2009.
>> PubMed Abstract

Stockdale HD, Givens MD, Dykstra CC et al: Tritrichomonas foetus infections in surveyed pet cats, Vet Parasitol 160:13, 2009.
>> PubMed Abstract

More on cat health: Winn Feline Foundation Library
Join us on Facebook
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Hale S, Norris JM, Slapeta J: Prolonged resilience of Tritrichomonas foetus in cat faeces at ambient temperature, Vet Parasitol 166:60, 2009.

This study, from the University of Sydney, Australia, was designed to investigate two culture methods for Tritrichomonas foetus, and to evaluate the effect of sample storage time on diagnostic utility. The two culture methods evaluated were InPouch TF-Feline (Bio-Med Diagnostics) and Modified Diamond's Medium. Two batches of normal cat feces were spiked with T. foetus prior to being stored either at room temperature or refrigerated. At different time points, small samples were taken from the original batches and tested in the culture systems. Both culture systems performed well. The accumulative sensitivity was found to be 83% and 100% for the InPouch TF-Feline and Modified Diamond's Medium respectively over a 6 hour period. The researchers were able to successfully culture T. foetus from feces that had been stored at room temperature for 24 hours. This finding may indicate that the environmental resilience of the organism may be more robust than previously thought, and that transmission may not be limited to close contact between cats. [SL]
>> PubMed Abstract

Related articles:
Tolbert MK, Gookin J: Tritrichomonas foetus: A New Agent of Feline Diarrhea, Compend Contin Educ Vet 31:374, 2009.
>> PubMed Abstract

Stockdale HD, Givens MD, Dykstra CC et al: Tritrichomonas foetus infections in surveyed pet cats, Vet Parasitol 160:13, 2009.
>> PubMed Abstract

More on cat health: Winn Feline Foundation Library
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Tritrichomonas in Cats in Italy

Holliday, M., D. Deni, and D.A. Gunn-Moore, Tritrichomonas foetus infection in cats with diarrhoea in a rescue colony in Italy. Journal of Feline Medicine & Surgery, 2009. 11(2): p. 131-134.

Tritrichomonus foetus is protozoan parasite causing diarrhea in cats. Clinical signs are those of large bowel diarrhea, and include increased frequency of defecation, semi-formed to liquid feces, foul-smelling feces with fresh blood and mucus, and fecal incontinence. Affected cats are typically well otherwise. There are various methods of diagnosing T. foetus infection in cats, such as PCR on feces and fecal culture. Most reports of T. foetus infection in cats have come from the U.S., but there are a few reports from other countries, such as the U.K. and Germany. In this report, fecal samples from 74 cats with chronic large bowel diarrhea living in a rescue colony in Tuscany were submitted for T. foetus diagnostics. Most were rescued street cats, but some were surrendered by owners. Of the 74 cats, almost 1/3 were found to be infected with T. foetus. The infected cats were predominantly over a year of age and were all neutered non-pedigreed, domestic cats. The investigators conclude that the prevalence of T. foetus may be more widely distributed than previously thought. [SL]
>> PubMed Abstract

Related articles:
Stockdale, H.D., et al., Tritrichomonas foetus infections in surveyed pet cats. Vet Parasitol, 2009. 160(1-2): p. 13-7.
>> PubMed Abstract

Frey, C.F., et al., Intestinal Tritrichomonas foetus infection in cats in Switzerland detected by in vitro cultivation and PCR. Parasitol Res, 2009. 104(4): p. 783-88.
>> PubMed Abstract

More on cat health: Winn Feline Foundation Library
Join us on Facebook

Holliday, M., D. Deni, and D.A. Gunn-Moore, Tritrichomonas foetus infection in cats with diarrhoea in a rescue colony in Italy. Journal of Feline Medicine & Surgery, 2009. 11(2): p. 131-134.

Tritrichomonus foetus is protozoan parasite causing diarrhea in cats. Clinical signs are those of large bowel diarrhea, and include increased frequency of defecation, semi-formed to liquid feces, foul-smelling feces with fresh blood and mucus, and fecal incontinence. Affected cats are typically well otherwise. There are various methods of diagnosing T. foetus infection in cats, such as PCR on feces and fecal culture. Most reports of T. foetus infection in cats have come from the U.S., but there are a few reports from other countries, such as the U.K. and Germany. In this report, fecal samples from 74 cats with chronic large bowel diarrhea living in a rescue colony in Tuscany were submitted for T. foetus diagnostics. Most were rescued street cats, but some were surrendered by owners. Of the 74 cats, almost 1/3 were found to be infected with T. foetus. The infected cats were predominantly over a year of age and were all neutered non-pedigreed, domestic cats. The investigators conclude that the prevalence of T. foetus may be more widely distributed than previously thought. [SL]
>> PubMed Abstract

Related articles:
Stockdale, H.D., et al., Tritrichomonas foetus infections in surveyed pet cats. Vet Parasitol, 2009. 160(1-2): p. 13-7.
>> PubMed Abstract

Frey, C.F., et al., Intestinal Tritrichomonas foetus infection in cats in Switzerland detected by in vitro cultivation and PCR. Parasitol Res, 2009. 104(4): p. 783-88.
>> PubMed Abstract

More on cat health: Winn Feline Foundation Library
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Tritrichomonas Diarrhea in Cats

Stockdale HD, Givens MD, Dykstra CC, et al. Tritrichomonas foetus infections in surveyed pet cats. Vet Parasitol 2009;160:13-17.

Tritrichomonas foetus causes chronic large bowel diarrhea in cats associated with blood or mucus, flatulence, tenesmus, vomiting, weight loss, and anal irritation. Most reports in the literature are since 1996. The objective of this was to estimate the prevalence of T. foetus in pet cats across the United States. Fecal samples from 173 cats across the U.S. were submitted by veterinarians. Thirty-two pedigreed cats were represented. In this study population, 10% of the cats were positive for T. foetus. All positive cats had chronic large bowel diarrhea. There was no correlation between breed or gender and infection with T. foetus. Other enteric pathogens, such as Giardia and Cryptosporidium, were present in nine of the 17 positive cats. The results of this study suggest that trichomoniasis is a disease of younger male and female cats of all breeds. [SL]
>> PubMed Abstract

Related articles:
Gunn-Moore DA, McCann TM, Reed N, et al. Prevalence of Tritrichomonas foetus infection in cats with diarrhoea in the UK. J Feline Med Surg 2007;9:214-218.
>> PubMed Abstract

Gookin JL, Copple CN, Papich MG, et al. Efficacy of ronidazole for treatment of feline Tritrichomonas foetus infection. J Vet Intern Med 2006;20:536-543.
>> PubMed Abstract

More on cat health: Winn Feline Foundation Library

Stockdale HD, Givens MD, Dykstra CC, et al. Tritrichomonas foetus infections in surveyed pet cats. Vet Parasitol 2009;160:13-17.

Tritrichomonas foetus causes chronic large bowel diarrhea in cats associated with blood or mucus, flatulence, tenesmus, vomiting, weight loss, and anal irritation. Most reports in the literature are since 1996. The objective of this was to estimate the prevalence of T. foetus in pet cats across the United States. Fecal samples from 173 cats across the U.S. were submitted by veterinarians. Thirty-two pedigreed cats were represented. In this study population, 10% of the cats were positive for T. foetus. All positive cats had chronic large bowel diarrhea. There was no correlation between breed or gender and infection with T. foetus. Other enteric pathogens, such as Giardia and Cryptosporidium, were present in nine of the 17 positive cats. The results of this study suggest that trichomoniasis is a disease of younger male and female cats of all breeds. [SL]
>> PubMed Abstract

Related articles:
Gunn-Moore DA, McCann TM, Reed N, et al. Prevalence of Tritrichomonas foetus infection in cats with diarrhoea in the UK. J Feline Med Surg 2007;9:214-218.
>> PubMed Abstract

Gookin JL, Copple CN, Papich MG, et al. Efficacy of ronidazole for treatment of feline Tritrichomonas foetus infection. J Vet Intern Med 2006;20:536-543.
>> PubMed Abstract

More on cat health: Winn Feline Foundation Library

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Tritrichomonas Infection in the Uterus of a Cat

Dahlgren, S. S., B. Gjerde, et al. (2007). "First record of natural Tritrichomonas foetus infection of the feline uterus." J Small Anim Pract 48(11): 654-7.

Tritrichomonas foetus is an emerging intestinal parasite of cats, causing chronic large bowel diarrhea. In cattle, this protozoan parasite is a sexually transmitted pathogen, infecting the uterus of cows and the preputial cavity and urethral orifice of bulls. In this case report, the first feline record of T. foetus infection of the uterus is described in a 17-month old Exotic Shorthair queen in Norway with pyometra. This queen had no history of diarrhea. Three other cats in the cattery were diagnosed with T. foetus infection using PCR on fecal samples: a 4.5-year old Persian male with intermittent diarrhea, a 22-month old male Exotic Shorthair with normal feces, and a 2.5-year old female Persian with normal feces. Interestingly, T. foetus has never been identified in cattle in Norway, although it is a reportable disease.
>> PubMed abstract


Related articles:
Winn funded research
Kather, E. J., S. L. Marks, et al. (2007). "Determination of the in vitro susceptibility of feline Tritrichomonas foetus to 5 antimicrobial agents." J Vet Intern Med 21(5): 966-70.
>> PubMed abstract


More on cat health: Winn Feline Foundation Library

Dahlgren, S. S., B. Gjerde, et al. (2007). "First record of natural Tritrichomonas foetus infection of the feline uterus." J Small Anim Pract 48(11): 654-7.

Tritrichomonas foetus is an emerging intestinal parasite of cats, causing chronic large bowel diarrhea. In cattle, this protozoan parasite is a sexually transmitted pathogen, infecting the uterus of cows and the preputial cavity and urethral orifice of bulls. In this case report, the first feline record of T. foetus infection of the uterus is described in a 17-month old Exotic Shorthair queen in Norway with pyometra. This queen had no history of diarrhea. Three other cats in the cattery were diagnosed with T. foetus infection using PCR on fecal samples: a 4.5-year old Persian male with intermittent diarrhea, a 22-month old male Exotic Shorthair with normal feces, and a 2.5-year old female Persian with normal feces. Interestingly, T. foetus has never been identified in cattle in Norway, although it is a reportable disease.
>> PubMed abstract


Related articles:
Winn funded research
Kather, E. J., S. L. Marks, et al. (2007). "Determination of the in vitro susceptibility of feline Tritrichomonas foetus to 5 antimicrobial agents." J Vet Intern Med 21(5): 966-70.
>> PubMed abstract


More on cat health: Winn Feline Foundation Library

Read More