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T. foetus Diagnostic Laboratory


Trichomonads are protozoa that reside as parasites or commensals of moist, warm and anaerobic body cavities of their hosts. Approximately 19 years ago trichomonosis of the large intestine of the cat was described and identified as a cause of chronic diarrhea. The trichomonad  was identified as Tritrichomonas foetus with a genotype that is distinct form venereal T. foetus of cattle.

The infection is now recognized to be distributed worldwide and it is regarded as one of the most common infectious causes of colitis in the domestic cat. The infection is common in catteries and shelters, and while remission of diarrhea may occur over time, persistence of the infection is common and may be lifelong. Diagnosis is based on demonstration of T. foetus in feces on the basis of light microscopy, protozoal culture, or PCR amplication using species-specific primers. Feline T. foetus is resistant to all commonly used anti-protozoal drugs. Ronidazole is currently the only drug demonstrated to be effective in eliminating T. foetus 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 or not we should even bother trying to treat it.

We hope that you will find our website helpful as you navigate the difficulties in diagnosis and treatment of this important feline infection.

T. foetus PCR Testing 

You can make a difference. Help us in our fight against T. foetus infection!

  • Did you know that surveys have suggested that TF infects a significant percentage of cats, up to 30% of all purebreds?
  • Did you know that countless numbers of TF infected cats were euthanized / given up to shelters prior to our discovery of the only effective treatment, Ronidazole?
  • Do you know that Ronidazole doesn’t always cure a cat of TF?
  • The fight isn’t over. We need your help to support our efforts to improve diagnosis and treatment of TF infection

T. foetus Resources

Peer-reviewed Research Publications  

  1. Tolbert MK, Stauffer SH, Gookin JL. Cysteine protease activity of feline Tritrichomonas foetus promotes adhesion-dependent cytotoxicity to intestinal epithelial cells. Infect Immun 2014;82:2851- 2859. Funded by the Morris Animal Foundation and STRIVE.
  2. Winston, J, Neel JA, Pipersova I, Moroff S, Gookin JL. Cyniclomyces guttulatus infection in dogs: 19 cases (2006-2013). J Am Anim Hosp Assoc 2013 (In Press)
  3. Ghosh A, Borst L, Stauffer SH, Suyemoto M, Moisan P, Zurek L, Gookin JL. Mortality in foster-age kittens is associated with a shift from ileum mucosa-associated Enterococcus hirae to colonization by E. faecalis and enteropathogenic E. coli. J Clin Micro 2013;51:3567-3578. Funded by the Winn Feline Foundation.
  4. Tolbert MK, Stauffer SH, Gookin JL. Feline Tritichomonas foetus adhere to the intestinal epithelium by receptor-ligand dependent mechanisms. Vet Parasitol 2013;192:75-82. Funded by the Morris Animal Foundation.
  5. Papich MG, LeVine DN, Gookin JL, Davidson GS, Stagner WC, Hayes RB. Ronidazole pharmacokinetics in cats following delivery of a delayed release guar gum formulation. Vet Pharm Exp Therap 2013;36:399-407.
  6. Hutchins RG, Breitschwerdt EB, Cullen JM, Bissett SA, Gookin JL. Limited yield of diagnoses of intrahepatic infectious causes of granulomatous hepatitis from archival liver tissue. J Vet Diagn Invest 2012;24:888-894.
  7. Tolbert MK, Leutenegger CM, Lobetti R, Birrell J, Gookin JL. Species identification of trichomonads and associated coinfections in dogs with diarrhea and suspected trichomonosis. Vet Parasitol 2012;187:319-322.
  8. LeVine DN, Papich MG, Gookin JL, Davidson GS, Davis JL, Hayes RG. Ronidazole pharmacokinetics after intravenous and oral immediate-release capsule administration in healthy cats. J Fel Med Surg 2011;13:244-250.
  9. Nicklas JL, Moisan P, Stone MR, Gookin JL. In-situ molecular identification and histopathological characterization of enteroadherent Enterococcus hirae infection in pre-weaning aged kittens. J Clin Micro 2010;48:2814-2820. Funded by the Winn Feline Foundation.
  10. Gookin JL, Stauffer SH, Dybas D, Cannon DH. Documentation of in vivo and in vitro aerobic resistance of feline T. foetus isolates to ronidazole. J Vet Intern Med 2010;24:1003-1007.
  11. Gookin JL, Stone MR, Yaeger MJ, Meyerholz DK, Moisan P. Fluorescence in-situ hybridization for identification of Tritrichomonas foetus in formalin-fixed and paraffin-embedded histological specimens of intestinal trichomonosis. Vet Parasitol 2010;172:139-143.
  12. Gray SG, Hunter S, Stone MR, Gookin JL. Assessment of reproductive tract disease in cats at risk for enteric Tritrichomonas foetus infection. Am J Vet Res 2010;71:76-81. Funded by the Winn Feline Foundation.
  13. Tolbert MK, Gookin JL. Tritrichomonas foetus infection – a new agent of feline diarrhea. Compend Contin Educ Pract Vet 2009;31:374-381.
  14. Bissett SA, Coccaro, MR, Malik R, Norris JM, O’Brien C, Gowan RA, Mansfield CS, Nicholls J, Griffin A, Gookin JL. Observed occurrence of Tritrichomonas foetus and other enteric parasites in Australian cattery and shelter cats. J Fel Med Surg 2009; 11:803-807.
  15. Davis JL and Gookin JL. Antiprotozoal Drugs. In Rivere and Papich eds. Veterinary Pharmacology and Therapeutics. 9th Ed. Blackwell Publishing. 2009;1145-1179.
  16. Bissett SA, Gowan RA, O’Brien C, Coccaro, MR, Gookin JL. Feline diarrhoea associated with Tritrichomonas foetus and Giardia coinfection in an Australian cattery. Aus Vet J 2008; 86(11):440- 443.
  17. Stauffer SH, Birkenheuer AJ, Levy MG, Marr H, Gookin JL. Evaluation of four DNA extraction methods for the detection of Tritrichomonas foetus in feline stool specimens by polymerase chain reaction. J Vet Diagn Invest 2008;20:639-641.
  18. Gookin JL, Stauffer SH, Coccaro MR, Poore MF, Levy MG, Papich MG. Efficacy of tinidazole for treatment of cats experimentally infected with Tritrichomonas foetus. Am J Vet Res; 2007;68:1085- 1088. Funded by Presutti Pharmaceuticals.
  19. Gookin JL, Stauffer SH, Coccaro MR, Marcotte M, Levy MG. Optimization of a species-specific PCR assay for identification of Pentatrichomonas hominis in canine fecal specimens. Am J Vet Res 2007;68:783-787.
  20. Gookin JL, Stauffer SH, Levy MG. Identification of Pentatrichomonas hominis in feline fecal samples by polymerase chain reaction assay. Vet Parasitol; 2007;145,11-15.
  21. Gookin JL, Copple CN, Papich MG, Poore M, Stauffer SH, Birkenheuer AJ, Twedt DC, and Levy MG. Efficacy of ronidazole for treatment of feline Tritrichomonas foetus infection. J Vet Intern Med 2006; 20:536-543. Supported by North Carolina State University appropriated funds.
  22. Gookin JL. Tritrichomonas. In Bonagura JD ed. Current Veterinary Therapy XIV. 14th Ed. W.B. Saunder’s Co. Philadelphia, 509-512.
  23. Gookin JL. Trichomoniasis. In Infectious Diseases of the Dog and Cat. 3rd Ed. CE Green Editor. W.B. Saunder’s Co. Philadelphia, 2006; 740-744.
  24. Yaeger M, Gookin JL. Histologic features of Tritrichomonas foetus colitis in domestic cats. Vet Pathol; 2005; 42: 797-804.
  25. Gookin JL, Birkenheuer AJ, St. John V, Spector M, and Levy M. Molecular characterization of trichomonads from feces of dogs with diarrhea. J Parasitol; 2005;91:939-943.
  26. Foster DM, Gookin JL, Poore MF, Stebbins ME, and Levy MG. Outcome of cats with diarrhea and Tritrichomonas foetus infection. J Am Vet Med Assoc 2004;225:888-892.
  27. Gookin JL, Stebbins ME, Hunt E, Burlone K, Fulton M, Hochel R, Talaat M, Poore M, and Levy MG. Prevalence of and risk factors for Tritrichomonas foetus and Giardia infection. J Clin Micro 2004;42:2707-2710. Selected in 2007 by the Faculty of 1000 Biology as “one of the most interesting papers published in the biological sciences, based on the recommendations of over 2000 of the world’s top researchers”.
  28. Gookin JL, Foster DM, Poore MF, Stebbins ME, Levy MG. Use of a commercially available culture system for diagnosis of Tritrichomonas foetus infection in cats. J Am Vet Med Assoc 2003;222:1-4.
  29. Levy MG, Gookin JL, Poore MF, Dykstra M, Litaker RW. Tritrichomonas foetus and not Pentatrichomonas hominis is the etiologic agent of feline trichomonal diarrhea. J Parasitol 2003;89:99-104.
  30. Gookin JL, Birkenheuer AJ, Breitschwerdt EB, Levy MG. Single-tube nested PCR for diagnosis of Tritrichomonas foetus in feline feces. J Clin Micro 2002;40:4126-4130.
  31. Gookin JL, Levy MG, Law JM, Papich MG, Poore MF, Breitschwerdt EB. Experimental infection of cats with Tritrichomonas foetus. Am J Vet Res 2001;62:1690-1697. Funded by Fort Dodge Animal Health.
  32. Gookin JL, Breitschwerdt EB, Levy MG, Gager RB, Benrud JG. Diarrhea associated with trichomonosis in cats. J Am Vet Med Assoc 1999;215:1450-1455. 33. Gookin JL, Riviere JE, Gilger BC, Papich MG. Acute Renal Failure In Four Cats Treated with


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You can make a difference. Help us in our fight against T. Foetus infection!

Make a tax-deductible donation to STRIVE – Support for T. foetus Research Innovation and Veterinarian Education – by clicking on the button below. You will be directed to the Giving web page. Go to the bottom of the page and select “I would like to give to a fund not listed here”. Write STRIVE in the pop-up box and click “add to cart”. Then hit continue. Enter the amount of your gift and payment information.

Research Team

Diagnostic Lab Contact: 919.513.6365