Tritrichomonas foetus in young cats with chronic diarrhoea: Comparison of the different diagnostic methods.
Summary
Tritrichomonas foetus has recently been identified as a cause of chronic diarrhoea in young cats. Up until recently, there was no effective treatment for T. foetus infection in cats. Recently, they have found that ronidazole (30-50 mg/kg q24h) for 14 days results in longterm elimination of T. foetus infection. Because of the serious adverse effects of ronidazole, a successfully diagnostic method is very important. The specific aims of the present study were to compare the different diagnostic methods (PCR at feces, fecal culture in the In Pouch TF® medium and PCR at In Pouch TF® medium), to determine the detection limits of our PCR and to determine the shedding pattern of the parasite through longitudinal followup study of infected cats.
Based on the results of our study, we can conclude that PCR at In Pouch TF® medium is the most sensitive diagnostic method for detection of a T. foetus infection. Based on a comparison of the different diagnostic methods, we concluded a relative efficacy for the detection of T. foetus organisms to be as follows: PCR at feces < fecal culture in In Pouch TF® medium < PCR at In Pouch TF® medium.
Results of our longitudinal followup study have shown that we can not detect T. foetus by PCR assay in all collected fecal samples and that we can speak of intermittent shedding of the parasite in measurable levels by PCR at feces.
The absolute detection limit of our realtime PCR was 10 organisms per 200 μl, the practical detection limit in feces we can not determine in our study, while the practical detection limit in In Pouch TF® medium sediment was 10 organisms per 200 μl.