Tritrichomonas spp

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Tritrichomonas foetus under light microscopy[1]

Tritrichomonas spp are a ubiquitous flagellated protozoan parasite found in dogs worldwide.

Co-infections with other intestinal protozoa are common and this parasite is not thought to be a primary initiator of disease.

Pentatrichomonas hominis infection is more frequently identified than T. foetus infection in diarrheic dogs with trichomonosis[2], unlike cats, where the converse is true.

Infections with other protozoa such as Giardia spp, Neospora spp[3] and Cryptosporidium spp also occur.

Species which are pathogenic to dogs include:

  • Tritrichomonas foetus

In dogs, tritrichomonas infections are often related to intermittent diarrhea, but most dogs are asymptomatic.

Treatment is usually effective with ronidazole, metronidazole or secnidazole.

As is observed with Giardia spp infections, elimination of all parasites are never 100% successful and re-emergence of infections are common, particularly in kenneled dogs[4].


  1. Starcentral
  2. Tolbert MK et al (2012) Species identification of trichomonads and associated coinfections in dogs with diarrhea and suspected trichomonosis. Vet Parasitol 187(1-2):319-322
  3. Cole RA et al (1993) Detection of Neospora caninum in tissue sections using a murine monoclonal antibody. J Vet Diagn Invest 5(4):579-584
  4. Fiechter R et al (2012) Control of Giardia infections with ronidazole and intensive hygiene management in a dog kennel. Vet Parasitol 187(1-2):93-98