The Unseen Enemy: Understanding & Managing Tritrichomonas in Cats

January 9, 2025

Tritrichomonas foetus (Tritric) is a microscopic menace that can turn a household into a battleground of chronic illness. This protozoan parasite often leads to persistent, hard-to-treat diarrhea in cats — especially when litter boxes and living spaces aren’t carefully managed.

While Tritric can infect dogs, it is far more common in cats — particularly young, purebred breeds living in multi-cat environments.

Dr. Sue Lim, an assistant professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences, and Kristen Flitcroft, a veterinary technician with firsthand experience, provide essential insights into recognizing, diagnosing, and managing Tritric infections.

Spotting the Signs

Tritric settles in the large intestine, causing intermittent or continuous digestive issues. Some infected cats exhibit foul-smelling, mucus-filled diarrhea — one of the most noticeable symptoms.

“Other symptoms include straining during defecation, anal swelling, and fecal incontinence — leaking stool without control,” Lim said.

The parasite — shed from the gastrointestinal tract into the feces — spreads when other pets come into contact with contaminated waste. For many cats, this occurs when grooming themselves or other cats.

Lim recommends testing and isolating new cats before introducing them into a multi-cat household to prevent the spread of this parasite.

“Isolation allows time to monitor for signs of infection,” Lim said. “Testing is especially important because even cats without symptoms can carry and spread the parasite.”

Flitcroft experienced the consequences of skipping these precautions firsthand and shared the toll it took on her household.

“I adopted a kitten and didn’t separate him from my other cats, and he quickly spread the parasite,” Flitcroft said. “The smell of their waste was unbearable, and there were messy footprints everywhere — even on the countertops.”

Diagnosing Tritric

Identifying Tritric can be challenging because its symptoms often closely resemble those of other gastrointestinal conditions, and many infected cats display no visible signs.

“Unfortunately, many vet offices don’t routinely test for Tritric,” Flitcroft said. “Unless an observant owner notices subtle abnormalities — such as soft stool — and seeks veterinary care, the parasite can go undiagnosed and continually spread to other cats.”

Veterinarians have several diagnostic methods to detect the parasite, each with its own advantages and limitations. The simplest option, fecal cytology, examines a stool smear under a microscope, but it isn’t the most accurate test.

“This method may miss the parasite if the infection is low-level or if the parasite is only shed occasionally,” Lim said.

A more reliable method is the InPouch test, which cultures the stool to grow the parasite. While this method increases accuracy, it requires more time to deliver results.

For the fastest and most accurate detection, Lim suggests the PCR assay, which looks for the parasite’s DNA in a stool sample.

Managing & Preventing Infection

Treating Tritric typically begins with administering an antibiotic daily for 14 days, which is currently the most effective solution. However, success also hinges on rigorous cleaning routines to prevent reinfection.

“The parasite can survive outside the cat’s body and linger in the environment,” Lim said. “Bleaching litter trays daily and drying them in the sun are essential steps to eliminate the parasite, along with retesting after treatment to confirm the infection is cleared.”

Flitcroft implemented Lim’s strict hygiene recommendations to manage the infection in her multi-cat household.

“I also disposed of waste immediately and frequently wiped down the litter area,” she said. “It was exhausting, but it paid off — after one round of treatment, my cats were parasite-free.”

It’s equally important to keep cats clean — as the parasite can cling to dirty fur and create another avenue for reinfection — and as stress-free as possible.

“Stress weakens a cat’s immune system, making them more susceptible to infection,” Lim said. “A calm, clean environment will support their overall health and make it harder for infections to take hold.”

Although managing Tritric can feel overwhelming, recovery is achievable — some cats even develop immunity as they age. With dedication, awareness, and perseverance, pet owners can protect their feline companions from this unseen enemy.

Pet Talk is a service of the College of Veterinary Medicine & Biomedical Sciences, Texas A&M University. Stories can be viewed on the web at vetmed.tamu.edu/news/pet-talk. Suggestions for future topics may be directed to vmbs-editor@tamu.edu.

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