Trichomonosis in cats with diarrhoea in Hong Kong, China, between 2009 and 2014

CASE SERIES SUMMARY: Infection of the domestic cat by Tritrichomonas blagburni, previously referred to as T foetus, may lead to a disease called feline trichomonosis, which manifests clinically as large bowel diarrhoea. The disease has a wide geographical distribution, including numerous countries in Europe, North America and Australia/Oceania. Nevertheless, it has occasionally been reported in Asia, South Korea and Japan. A retrospective study was carried out to include all domestic cats with diarrhoea, presented to two veterinary clinics in Hong Kong, China, between 1 July 2009 and 30 June 2014. A total of 29 cats with diarrhoea were diagnosed with Tritrichomonas species infection by means of quantitative PCR and direct microscopy. Tritrichomonas species was more frequently found in young (median age 10 months), male (66%) and purebred cats (86%). Giardia species was found in 31% of Tritrichomonas species-positive cats. The recommended dose of ronidazole (30 mg/kg q24h for 14 days) resolved clinical signs in 83% of diagnosed cats. RELEVANCE AND NOVEL INFORMATION: This case series describes Tritrichomonas species as a cause for feline chronic diarrhoea in cats in China. The high rate of failure (17%) in those cats receiving a standard regimen of ronidazole might be due to owner or patient compliance rather than protozoal resistance to the drug.