Sarcocystis Infection (Sarcocystosis) in Cats What To Know About Feline Sarcocystosis and How to Treat It

Sarcocystis Infection (Sarcocystosis) in Cats

Sarcocystosis is a parasite infection that affects domestic and wild cats, as well as other animals. Learn more about this condition here.

Sarcocystosis is a parasitic disease that affects both domestic and wild cats, as well as other mammals. The infection is caused by a type of parasite called Sarcocystis, which invades the muscles of the host animal and forms cysts. Although sarcocystosis is generally not life-threatening to cats, it can cause serious symptoms that can affect the animal's quality of life. 

In this article, we will explore the causes, symptoms, and treatments for sarcocystosis in cats and what you can do to prevent your feline companion from becoming infected.


Sarcocystosis in cats is caused by a microscopic parasite called Sarcocystis. Cats become infected by ingesting infected tissues, such as raw or undercooked meat, or by eating infected prey, such as mice or birds. The parasites then invade the muscles of the cat and form cysts. In some cases, the cysts can remain in the muscle tissues for long periods of time, causing chronic infections. Sarcocystosis is most commonly seen in cats that hunt, but it can also occur in indoor cats that are fed raw or undercooked meat.

Through the sharing of food or water bowls or through mutual grooming, infected cats can also infect other cats. Although it is uncommon, the parasites can potentially be passed to humans. It's crucial to use appropriate hygiene while handling raw meat and to only serve properly prepared meat to cats in order to stop the spread of sarcocystosis.


The intensity of the infection and the location of the cysts influence the symptoms of a sarcocystis infection in cats. Common signs include:

  • Weakness in muscles

  • Appetite loss

  • Weight loss

  • Depression

  • Exercise intolerance

  • Lameness

  • Muscle twitching

  • Muscle pain and tenderness

In extreme cases, the cysts can cause muscle degeneration and even paralysis. Take your cat to the vet for a diagnosis and treatment if you think it may have sarcocystosis.


Sarcocystosis in cats can be difficult to identify., as the symptoms can be similar to those of other muscle or nerve disorders. A veterinarian will do a comprehensive physical examination and inquire about the cat's medical history, including nutrition and any recent changes in behavior, in order to identify sarcocystosis.

A veterinarian may perform the following diagnostic procedures in addition to a physical examination to determine the existence of sarcocystosis:

  • Blood tests: To assess any raised muscle enzyme levels that could be a sign of muscle injury

  • Biopsy: It is possible to collect a small sample of muscle tissue for laboratory testing.

  • Imaging studies: The cysts can be seen, and their location and size can be determined by X-rays, ultrasonography, or MRI.

  • Serological tests: These tests detect antibodies produced by the immune system in response to the parasite

If sarcocystosis is confirmed, the veterinarian will develop a treatment plan based on the severity of the infection, the size and location of the cysts, and the general health of the cat.

Treating Sarcocystis Infection in Cats

The severity of the infection and the cat's general health will determine the course of treatment for cats with sarcocystosis. In most circumstances, medication and supportive care will be used in conjunction with treatment.

  • Medications: Anti-parasitic drugs may be prescribed to kill the Sarcocystis parasite and reduce inflammation. Depending on the extent of the illness and the cat's general condition, a specific medicine may be prescribed.

  • Supportive care: This may include rest and confinement to allow the infected muscles to heal, as well as pain management and anti-inflammatory medications to relieve pain and reduce inflammation. In severe cases, the cat may require nutritional support, such as special diets or supplements, to help them regain weight and strength. Further, make sure your cat has a safe and clean environment to help it with their recovery.

  • Surgery: The cysts may need to be removed surgically in some circumstances. Usually, this is only required in extreme circumstances when the cysts are really damaging the muscles or are in locations where they are challenging to cure medically.

With enough treatment and care, most cats with sarcocystosis will recover fully, although the recovery time can vary depending on the extent of the infection. Nevertheless, follow your veterinarian's instructions and bring your cat back for follow-up exams to monitor their progress and to ensure the infection has been fully treated.

Prevention is also important in reducing the risk of sarcocystosis in cats. This entails keeping cats from hunting or consuming contaminated prey, giving them only properly cooked meats, and maintaining appropriate hygiene while handling raw meat. Sarcocystosis and other parasitic illnesses can be prevented with routine veterinary exams and parasite control techniques.

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