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 30 mg/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.