͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ ͏‌ 
Is this email not displaying correctly? View it in your browser.
Image description

Tritrichomonas Infection in Cats

Image description

Tritrichomonas foetus is a significant cause of large bowel diarrhea and persistent colitis in cats. These pear-shaped organisms have three anterior flagella and one posterior flagellum. They have a distinctive undulating membrane, which gives them a similar appearance to Giardia. However, they do not form cysts and are transmitted directly from one host to another as trophozoites.

The infection is most prevalent among young cats living in close quarters, such as in densely populated catteries and shelters. A notable investigation into purebred show cats discovered a 31% infection rate among 117 cats spanning 89 catteries, as detailed in Gookin's 2004 study

Clinical Signs

Image description

Some cats infected with T. foetus may not exhibit any symptoms, particularly older cats that are in good health. However, most cats with T. foetus infection suffer from mild to severe lymphoplasmacytic and neutrophilic colitis, which causes recurrent episodes of large bowel diarrhea that may vary in consistency from semiformed to "cow pie" and emit a foul odor. Diarrhea may contain fresh blood or mucus. In severe cases, kittens may experience painful anal irritation, fecal incontinence, or even rectal prolapse. Affected cats usually maintain a healthy appearance and good body condition overall. The presence of diarrhea can be exacerbated by other intestinal infections or parasites, particularly Giardia and Cryptosporidium.


To confirm the infection of T. foetus, there are three methods available - direct fecal microscopy, fecal culture, and fecal polymerase chain reaction (PCR) assay.

Direct fecal microscopy involves identifying the motile trophozoites T. foetus in fresh wet smears of diarrheic feces taken directly from the rectum. This method identifies the organisms in about 14% of cases and is less effective with formed or dried feces. In cats who have been treated with antibiotics recently, the detection rate decreases. Trichomonads, which resemble Giardia in size and shape, can be distinguished by their unique undulating membrane and rapid, jerky motility, contrasting with Giardia's "falling leaf" movement.

Fecal culture can be done in-house or at a specialized lab. It helps increase the chances of identifying the organisms. In specific cases, a saline flush might be performed by inserting a catheter through the cat's anus to wash the colon with saline, followed by aspiration of fecal material.

Fecal PCR is the most accurate method for identifying T. foetus. To perform this test, the fecal sample should not contain any litter. This technique detects the organism's DNA traces in the cat's stool.

It's best to conduct testing on cats that have not received antibiotics for at least two weeks for the most accurate test results. Antibiotics can temporarily reduce the number of T. foetus, leading to false negatives.


Often, many approaches for treating chronic diarrhea have been tried unsuccessfully before a true diagnosis of T. foetus is confirmed.

Tritrichomonas foetus
is resistant to most antibiotics and is extremely difficult to eradicate (Gookin 2001). Numerous antibiotics have been evaluated. Some antibiotics reduce the number of organisms and improve the diarrhea without eliminating the infection, so diarrhea relapses whenever antibiotics are stopped. Diarrhea is typically refractory to corticosteroids.

The most successful treatment for eliminating T. foetus is ronidazole (30 mg/kg PO, once or twice daily for 14 days). The side effects in some cats include lethargy, decreased appetite, and neurotoxicity. Cats with neurotoxic signs usually improve when the drug is stopped, but recovery can take 1 to 4 weeks. Ronidazole should not be used in pregnant and nursing queens or in very young kittens. Ronidazole is not approved for veterinary or human use, but some pharmacies compound chemical grade ronidazole for veterinary use. Because of its bitter taste, ronidazole compounded in gel caps is better tolerated than flavored suspension. When prescribing ronidazole obtain informed consent and instruct owners to wear protective gloves when handling it.

Management of Tritrichomonas foetus Infection

In cases where cats show mild or sporadic symptoms of diarrhea caused by T. foetus, and treatment is not possible due to potential side effects, costs, or the owner's preferences, it is important to know that diarrhea may naturally go away with time, which can take up to two years. However, such cats are likely to remain lifelong carriers of the parasite.

The outlook for cats receiving treatment is generally positive. A majority of treated cats exhibit better stool consistency in just a few days, though diarrhea might linger briefly as related secondary inflammation subsides. Nonetheless, around 25% of cases might experience a continuous infection despite initial treatment.

Fortunately, T. foetus has a short lifespan outside its host and is easily neutralized by common disinfectants. To mitigate infection risks, it's advised to uphold strict litter box cleanliness through daily cleansing, isolate cats under treatment, minimize stress factors, prevent overcrowding, and implement regular screenings in breeding and shelter settings whenever feasible.


Bioguard’s Qmini PCR can detect T. foetus DNA in 90 minutes at your clinics using feces as samples.

To learn more about Qmini PCR, click here

Want to stay up-to-date with what is going on?

Image description
Image description
Image description

Follow our Pages for the latest updates

FHV Ag/ FCV Ag Combo Test: Detection of Viral-Induced Upper Respiratory Tract Disease in Cats

If your cats are often seen scratching at their eyes, nose, and mouth, exhibit choking sounds while breathing, or show difficulty swallowing, these symptoms may signal the early stages of an upper respiratory infection.

Bioguard offers a leading diagnostic solution for quickly identifying the primary culprits behind most feline upper respiratory illnesses: Feline Herpesvirus (FHV-1) and Feline Calicivirus (FCV). The FHV Ag/FCV Ag Combo Test is designed as a sandwich lateral flow immunochromatographic assay, making it straightforward to rapidly detect the presence of FHV Ag and FCV Ag in your cat's ocular or nasal secretions.

Image description

To know more about this product, contact us directly at: [email protected]

Image description
Image description

For any direct inquiries, please contact us at: [email protected]

About Bioguard Corporation

The Bioguard is a company focusing on animal disease diagnostic services and products.
Our animal health diagnostic center is the first and only ISO/ IEC 17025 accredited animal disease testing laboratory in Taiwan and China.

Copyright © Bioguard Corp., All rights reserved.

Our mailing address is: [email protected]

If you want to unsubscribe, click here.