Toxoplasmosis is a type of infection commonly associated with domestic cats. Once cats are initially exposed to the parasite that causes toxoplasmosis, they begin actively shedding oocysts in their stool. 

Toxoplasmosis is considered a public health concern because the infection can pass from cats to people during this shedding stage. A study recently estimated that 37.5 percent of domestic cats worldwide have been exposed to the parasite that causes this infection as demonstrated by the presence of antibodies within their blood. Additionally, about 2.6 percent of cats were shedding oocysts in their stool indicating a current, active infection. 

Because infected cats can pose a risk to humans, pet parents should understand what toxoplasmosis is and how to prevent their cats from becoming infected.

What Is Toxoplasmosis?

Toxoplasmosis is an infection caused by a protozoan parasite called Toxoplasma gondii. It affects many different types of animals and can result in a wide variety of symptoms. It is relatively common in cats but most are asymptomatic despite being infected with the parasite. 

This disease is also zoonotic, which means that it can spread from cats to people. Outdoor cats are much more likely to become infected compared to indoor cats due to their likelihood of coming into contact with contaminated soil or other animals who may be carrying the parasite.  

Causes of Toxoplasmosis in Cats

Cats can get toxoplasmosis when they ingest an infected rodent or bird, raw meat, or contaminated fecal material within the environment. 

In as little as three days after becoming infected, cats begin to shed oocysts in their stool. Shedding may continue for up to 20 days. After the oocysts are passed by the cat and exposed to the environment, they become infectious and can cause disease in other animals or people if accidentally ingested. Infected cats usually only actively shed oocysts once in their lives after their first exposure to Toxoplasma gondii. However, the parasite can enter the tissues of the cat and cause a chronic, inactive infection. If a cat becomes immunosuppressed, re-shedding of oocysts may occur.

Since toxoplasmosis can be passed from cats to humans, it is understandable that many pet parents may be concerned about exposure. This transmission occurs through accidental ingestion of infected fecal material, not by simply breathing in cat litter. Accidental ingestion can occur if a pet parent cleans the litter box of an infected cat and forgets to wash his or her hands afterwards before touching his or her mouth or eating a meal. Practicing good hand hygiene when tending to the litter box, such as wearing gloves and washing hands, can reduce the risk of infection in people.

Toxoplasmosis Symptoms in Cats

Many healthy cats do not show any signs that they have been infected by Toxoplasma gondii. However, when cats do show symptoms, they can be highly variable depending on the cat’s health status and age. 

Symptoms that may be seen in cats with toxoplasmosis include:

• Fever
• Lethargy
• Low appetite
• Difficulty breathing
• Jaundice
• Diarrhea
• Vomiting

This infection can also negatively affect the brain and eyes in some cats. Infected cats may experience the following symptoms:

• Confusion
• Incoordination
• Abnormal behaviors
• Head pressing
• Vocalizing
• Seizures
• Localized or generalized eye inflammation

Diagnosing Toxoplasmosis in Cats

Veterinarians will start with a physical exam and take a history from the pet parent to identify any abnormalities or clues as to what might be affecting the cat. If toxoplasmosis is suspected, a stool sample can be collected and examined under the microscope to identify oocysts that the cat may be shedding. Blood and other body fluids may be sent to a laboratory for more specific testing. 

Diagnosis can also be made by sending a tissue sample to a pathologist for review; however, this can be costly and is typically done post-mortem. Additional testing, such as X-rays, a neurological exam, and an eye exam can be performed to support a diagnosis of toxoplasmosis.

Toxoplasmosis Treatment in Cats

Clindamycin, an antibiotic, is commonly prescribed for a period of 3 to 4 weeks to treat toxoplasmosis in cats. An anti-parasitic medication known as pyrimethamine in combination with an antibiotic called sulfadiazine may also be used. In many instances, no treatment is necessary in cats.

Some cats may require hospitalization if they are very ill from the infection. Treatment may consist of intravenous fluids and other necessary supportive care, such as oxygen therapy, until they are feeling better. Cats may be given additional treatment based on their presenting symptoms at the discretion of the veterinarian.

Treatment costs for toxoplasmosis can vary greatly depending on the symptoms the cat is experiencing and the types of treatment being administered. Clindamycin is given orally at home and can range from $20-$30 for a course of treatment. Supportive care or hospitalization can range from $500 or more. 

Follow up stool testing to identify whether oocyst shedding has stopped can also add additional costs to the final bill.

How to Prevent Toxoplasmosis in Cats

The best preventative measure pet parents can take to reduce the risk of toxoplasmosis in their cats is to keep them indoors. Since rodents are a reservoir for infection, ensuring the home is rodent-free is critical. 

If a cat does become infected, it is important to separate him from other cats within the household. This includes providing separate food and water bowls, separate bedding, and a separate litter box until the shedding of oocysts stops.  

If pet parents are unable to keep their cats inside, deterring rodents and birds from the property is helpful. Ensure outdoor cats always have access to clean, fresh water so they are not tempted to search for other water sources that could potentially be contaminated. Feeding cats dry food rather than a raw diet also reduces their risk of contracting the infection.

Pet parents may also be interested in learning how they can prevent infection in themselves if their cat is diagnosed with toxoplasmosis. Cleaning the litter box every day can greatly reduce the risk of cat to human transmission. Oocysts that have been shed by an infected cat must be exposed to the environment for one to five days before becoming infectious. The exact time period will depend on environmental conditions, but cleaning the litter box each day is an important guideline to follow. 

Pet parents should always wash their hands after tending to the litter box or after coming into contact with any areas outdoors, such as sandboxes, that cats may have defecated in as well.