Thread: Tritrichomonas Foetus

Treatment

Most studies on treatment of T. foetus infection in cats have been unrewarding. The organism is resistant to most traditionally used anti-protozoal drugs such as fenbendazole and metronidazole. The use of a variety of different antimicrobial drugs has been reported to improve fecal consistency during therapy of infected cats, possibly because of interaction between T. foetus and the bacteria normally present in the intestine. However, such antibiotic use is not recommended as it may ultimately prolong the shedding of the organism, and does not resolve the underlying problem.

A recent study by Dr Jody Gookin at the North Carolina State University (who has performed most of the work on this infection in cats) identified that ronidazole (an antibiotic similar but not the same as metronidazole) may have good efficacy against T. foetus infection in cats (JVIM, 2006;20;536). From limited studies its use appears to be relatively safe in cats, although a small number of patients have developed neurological signs e.g. twitching and seizures, which have resolved on stopping the drug. (The neurological signs are similar to those seen in some kittens, or cats with liver disease, when they are given standard or high doses of metronidazole). Ronidazole should be used with caution. Initial studies suggested that a dose of 30-50mg/kg once to twice daily for two weeks is capable of both resolving clinical signs and potentially eradicating the T. foetus. However, keeping to the lower end of the dose is advisable (30mg/kg), as is giving it only once daily, and reducing it even further for young kittens or cats with hepatopathy; (10mg/kg once daily for two weeks). To ensure that each kitten receives the correct dose, and so reduce the risk of side effects, it is also important to weigh the kittens prior to ordering the reformulated capsules. The bitterness of the powder means that it must be placed in capsules prior to administration.
Ronidazole (10% powder preparation) is commonly used to treat trichomoniasis in birds (e.g. pigeons). However, it is not available in this form in the UK, and the consistency of the 10% formulation is difficult to guarantee. Therefore, we have gained permission from the Veterinary Medicines Directorate (VMD) to use 100% pure chemical grade ronidazole to treat T. foetus infected cats. This is the form that is now used in the USA. In the UK it can be obtained upon receipt of a signed named-animal prescription as capsules from Nova Laboratories, Tel: 0116 223 0099. While the VMD have agreed to our use of this chemical in these cats, they strongly recommend that detailed records are maintained and that no cat is treated without first obtaining informed, signed, owner consent.

Careful handling of the drug is therefore advised. It should never be given to pregnant queens (or queens about to be put to stud): it is very teratogenic and may result in a number of different and severe defects.

Can T. foetus infect people?
It is thought that T. foetus is unlikely to infect humans; however as a precaution people in contact with infected cats are advised to take basic hygiene precautions to avoid ingesting the parasite. These precautions will also help to prevent the spread of the infection to other cats, and prevent humans from being infected with other infections that the cat may carry.
Suitable hygiene precautions include:

* Washing hands thoroughly after handling cat faeces
* Washing hands thoroughly after cleaning cat litter trays, whether the cat has diarrhea or not
* Cat scratches or bites should always be washed immediately with soap and water. Seek medical attention as soon as possible if signs of infection appear, such as redness, pain or swelling.
* Persons with a weakened immune system should not handle their cat’s feces or litter box, they are advised to wash their hands after handling their cats, and they are advised not to keep cats that have persistent diarrhea. If their cat develop diarrhea it should be fully investigated and if found to be infected with Tritrichomonas foetus it should be treated with ronidazole and then re-tested, or (at least temporarily) re-homed until the infection has resolved.