Crazy Anteater Trichs: Tetratrichomonad-Associated Diarrhea in a Giant Anteater (Myrmecophaga tridactyla)
American Association of Zoo Veterinarians Conference 2009

Dalen W. Agnew1,2, DVM, PhD, DACVP; Steve Bolin1,2, DVM, PhD; Ailam Lim1,2, MS; Lisa Meader1, BS; Nicole Grosjean1, BS; Carol Flegler3, BA; Heather Jones4, VMD

1Diagnostic Center for Population and Animal Health, College of Veterinary Medicine, Michigan State University, Lansing, MI, USA; 2Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, Lansing, MI, USA; 3Center for Advanced Microscopy, Michigan State University, Lansing, MI, USA; 4Detroit Zoological Society, Royal Oak, MI, USA


A 14.5-year-old male giant anteater (Myrmecophaga tridactyla) had a history of prolonged and gradual weight loss with loose stool. Fecal samples examined 4 days before death revealed abundant fecal flagellated protozoa and necropsy demonstrated moderate colitis as well as pneumonia, cardiomyopathy, and glomerulosclerosis. Feces were cultured in specific trichomonad media (InPouch™, Biomed Diagnostics, White City, OR, USA) resulting in abundant growth of the parasite. Wright-Giemsa staining showed a 5–10 µm ovoid to pear-shaped trichomonad with 4–8 flagella. Scanning electron microscopy, including three-dimensional imaging, revealed an ovoid structure with a variable number of flagella and an undulating membrane. Polymerase chain reaction using primers that detected genomic DNA of trichomonad protozoa yielded an amplification product, while primers designed to detect genomic DNA of Tritrichomonas foetus did not produce an amplicon.2 Sequence analysis of the amplification product demonstrated 97% homology with Tetratrichomonas sp. and 91% homology with Tetratrichomonas buttreyi, an intestinal trichomonad of cattle.

The importance of the Tetratrichomonas to disease in the anteater is unknown. This anteater had significant pulmonary, cardiac, and renal disease which may have been exacerbated by chronic diarrhea and colitis. Tetratrichomonas buttreyi has been reported to proliferate in diarrheic feces,1 but trichomonads can also lead to chronic colitis, as seen in cats3. Further investigation into the fecal flora of normal and diarrheic anteaters will provide more information on the potential role of protozoans in intestinal disease.

Literature Cited

1.  Castella, J., E. Munoz, D. Ferrer, and J.F. Gutierrez. 1997. Isolation of the trichomonad Tetratrichomonas buttreyi (Hibler et al. 1960) Honigberg, 1963 in bovine diarrhoeic feces. Vet Parasitol. 70:41–45.

2.  Cobo, E.R., C.M. Campero, R.M. Mariante, and M. Benchimol. 2003. Ultrastructural study of a tetratrichomonad species isolated from prepucial smegma of virgin bulls. Vet Parasitol. 117:195–211.

3.  Gookin, J.L., E.B. Breitschwerdt, M.G. Levy, R.B. Gager, and J.G. Benrud. 1999. Diarrhea associated with trichomonosis in cats. J Am Vet Med Assoc. 215:1450–1454.


Speaker Information
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Dalen W. Agnew, DVM, PhD, DACVP
Diagnostic Center for Population and Animal Health
College of Veterinary Medicine
Michigan State University
Lansing, MI, USA

Department of Pathobiology and Diagnostic Investigation
College of Veterinary Medicine
Michigan State University
Lansing, MI, USA

Animal Behavior and Welfare Group
Michigan State University
East Lansing, MI, USA

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