Protozoan Infection (Trichomoniasis) in Cats

Trichomoniasis is among the most common causes of diarrhea in cats, especially for kittens under the age of one.

The condition is not considered a medical emergency as it is not life-threatening; nonetheless, medical attention is advised as trichomoniasis is often seen in cats suffering from co-infections or more serious underlying conditions.

Timely medical attention to determine possible underlying causes or secondary conditions is warranted for cats presenting with chronic diarrhea to prevent deterioration of the animal's quality of life.

Cats affected by trichomoniasis are likely to be infected with other protozoa. The most common co-infection is Giardia spp. Other possible parasitic co-infections include Isospora and Cryptosporidium. Symptoms are similar to Tritrichomonas.

Feline trichomoniasis is a large bowel infection caused by the single-cell protozoan parasite Tritrichomonas foetus. Once in a cats’ system, the parasite colonizes the large intestine causing inflammation and long-term diarrhea. The precise infection mechanisms are currently unknown, but it is thought to be transmitted via the fecal-oral route.

Tritrichomonas can infect cats of any age, breed and sex. However, kittens under the age of two are more likely to develop symptoms of the infection, with older cats more likely to be asymptomatic carriers.

A number of risk and predisposing factors can increase the chances of clinical infection; they include:

• FeLV and FIV
• Giardia, Isospora, and Cryptosporidium spp.
• A high number of cats living in the same environment
• Stress: stress factors vary from animal to animal; common causes include overcrowding, neutering, dietary changes, and environmental changes.

All of these factors can reduce cats’ immune response.

Due to the non-specific symptoms, diagnosis of trichomoniasis is not straightforward; the first step is ruling out other possible causes of diarrhea and co-existing conditions (e.g., giardiasis). Cats presenting symptoms of trichomoniasis undergo the following diagnostics:

• Medical history
• Physical examination
• Fecal smear
• Fecal culture and special fecal testing (PCR)
• Colonoscopy
• Biopsy (rare)

Once diagnosed, all felines in the household are recommended to be tested for trichomoniasis infection as some cats can be asymptomatic carriers.

While medication is available, it is only partially effective.

Treatment options for cats diagnosed with trichomoniasis include:

• Dietary changes: increasing the amount of fiber in the diet can firm up stool
• Probiotics: probiotics are useful in restoring the animal's healthy gastrointestinal flora
• Supportive care: patients may require fluid therapy to treat dehydration

Patients may be monitored for 2 to 3 weeks after treatment.

Treatment of trichomoniasis does not have a high success rate. The majority of affected felines are able to recover with no medical attention but may require up to two years for the symptoms to subside completely.

Affected patients are likely to relapse due to a number of factors:

• Diet
• Stress
• Other underlying conditions or co-infections

Cats affected by underlying conditions are more likely to suffer from complications.

Trichomoniasis is contagious and is thought to be spread via the fecal-oral route.

Prevention strategies include:

• Cleaning the environment frequently
• Clean litter boxes daily
• Disinfect litter boxes frequently
• Test all cats (asymptomatic cats included) in the household
• Keep infected and uninfected animals separate

Trichomoniasis is a common cause of chronic diarrhea in cats.

• Dietary changes
• Probiotics
• Supportive care