Babesiosis in Cats

Michael Kearley, DVM
By Michael Kearley, DVM on Aug. 9, 2022
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In This Article


What Is Babesiosis in Cats?

Babesiosis, previously called piroplasmosis, is a blood-borne parasite transmitted through the bite of a tick. It can affect a wide variety of animals, including humans. Specifically, Babesia felis is the protozoan parasite that affects cats. Though it can often have deadly consequences, this disease is fortunately not as common in the United States (though it is more prevalent where ticks are in abundance). It is seen more predominately in Southern Africa and other countries.

The parasite is ingested by a tick during its feeding stage and replicates within it. If it is inside a female carrying eggs, it will go on to affect the eggs. When the tick latches on and bites the cat, it will pour out (regurgitate) digestive enzymes to prevent the cat’s blood from clotting so it can continue feeding. It is during this regurgitation process that the disease is transmitted to the cat.

Once inside the cat’s bloodstream, the parasites attach to the red blood cells, replicate, and later rupture the cells. They then continue to infect other cells. Anemia (blood loss) usually develops within a few weeks, which can manifest as a lack of energy and appetite, and other serious and life-threatening complications. Of the cases reported, most infections seem to occur in younger cats. There doesn’t seem to be any specific breed or gender that is affected more than another.

Symptoms of Babesiosis in Cats

Tick-borne diseases are usually noticed within a few weeks after the original tick bite. You may notice your cat experiencing the following:

  • Lethargy

  • Lack of appetite

  • Anemia and secondary bruising, which may be noticed as pale gums, bloody stool, and/or a bloody nose

  • Jaundice (yellowing of the skin, eyes, or gums)

  • Fever (not as commonly reported)

In addition to the above symptoms, you may notice irritation, redness, and itching around the bite site.

Because babesiosis is transmitted through tick bites, be sure to check your cat thoroughly for ticks that are visible to the naked eye; usually the size of a tack or smaller, often darker in color, and have several pairs of legs. The most common areas ticks are found on a cat include the head, ears, neck, feet, and rear.  

Causes of Babesiosis in Cats

Cats acquire babesiosis most frequently through tick bites. Babesiosis has been found in multiple vertebrate species, including humans. Fortunately, it is not a zoonotic disease, meaning you cannot acquire the disease from your cat. Because it is a blood-borne parasite, it can be transmitted to other cats through bites, scratches, and even blood transfusions.

How Veterinarians Diagnose Babesiosis in Cats

Your veterinarian will conduct a physical exam and review the type and consistency of tick preventive given, if any. It is crucial to communicate to your veterinarian any previous tick bites and/or tick sightings in the environment, and discuss any recent travel outside of the United States, prior blood transfusions, and any recent bite wounds. Following this, your vet may also recommend the following:

  • Bloodwork (specifically a complete blood cell count), urine testing, and X-rays to assess your cat’s overall condition and to rule out other possibilities.

  • Microscopic review of a blood smear, often done by a veterinary clinical pathologist, to look for the pear-shaped organisms seen within the blood cells themselves.

  • PCR or antibody testing aimed at detecting the organism’s DNA.

  • Analysis of the tick itself, if recovered and brought in.

Treatment of Babesiosis in Cats

Primaquine phosphate, an anti-malarial drug, has been reported to be effective for the treatment of babesiosis. Antiprotozoal medications, such as imidocarb dipropionate, have also been used.

Depending on the severity of the infection and clinical signs noted, supportive care may be needed. This may include pain medications, blood transfusions, IV fluids, and appetite stimulants. If your cat requires a blood transfusion, it is extremely important to check its blood type first. Unfortunately, there is not a babesiosis vaccine approved for use on cats at this time.

Recovery and Management of Babesiosis in Cats

The timeline of recovery for a cat is dependent on the case. It often takes several doses of the medication—given multiple weeks apart— for full recovery to take place. PCR testing is often recommended as a follow-up to figure out the level and degree of infection and carrier status (if there was no previous infection). Most cats, if treated early during infection, will live normal and healthy lives.

If left untreated, your cat can experience complications, usually related to the anemia, but other complications can develop such as kidney disease, respiratory distress, and liver issues. For cats who recover, even though they can often remain asymptomatic, they will remain carriers of the disease for life, which means there may need to be some continual monitoring and considerations as other cats could become infected.

Prevention of Babesiosis in Cats

Preventing ticks on your cat is relatively effortless. There are many available and cost-effective products on the market that can be used to prevent fleas and ticks on cats. Be sure to partner with your veterinarian to find the product most suitable for you and your pet. Most products take several hours before they start killing and repelling ticks, so be mindful when planning outdoor activities. Ticks have been found throughout the United States and abroad, and it is recommended that you provide year-round protection and perform frequent, thorough checks for ticks on your cat.


  1. Hartmann K, Addie D, Belák S, et al. Babesiosis in cats: ABCD guidelines on prevention and management. J Feline Med Surg. 2013;15(7):643-646.

  2. Bosman AM, Penzhorn BL, Brayton KA, Schoeman T, Oosthuizen MC. A novel Babesia sp. associated with clinical signs of babesiosis in domestic cats in South Africa. Parasit Vectors. 2019;12(1):138.

  3. Bosman AM, Oosthuizen MC, Venter EH, Steyl JC, Gous TA, Penzhorn BL. Babesia lengau associated with cerebral and haemolytic babesiosis in two domestic cats. Parasit Vectors. 2013;6:128.

  4. American Association of Veterinary Parasitologists. Babesia felis.

  5. Potgieter FT. Chemotherapy of Babesia felis infection: efficacy of certain drugs. J S Afr Vet Assoc. 1981;52(4):289-293.

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Michael Kearley, DVM


Michael Kearley, DVM


Dr. Michael Kearley graduated from the University of Florida College of Veterinary Medicine in 2013. He graduated with a certificate in...

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