Babesiosis in Cats

Babesiosis is a protozoan disease that is likely spread by ticks. It is in the genus Babesia of protozoa, which includes one-celled organisms that are parasites of red blood cells. This disease occurs most commonly in dogs, but occasionally is reported in cats. Babesiosis occurs worldwide, but is most prevalent in cats in France, Germany, Thailand, and Zimbabwe. Young cats tend to become infected more often and with worse symptoms.

Signs & Symptoms of Feline Babesiosis

Pale tongue, gums, and nose due to severe deficiency of red blood cells
Rough hair coat
Loss of appetite
Lethargy
Enlarged lymph nodes

Cats with this disease often show no symptoms, though they do have the protozoa present in their bodies.

Causes of Feline Babesiosis

Babesia felis is the most common species of Babesia that infects cats. Transmission in cats is assumed to be by ticks, as this is the mode of transmission in canines, but this has not yet been proven.

Diagnosis of Feline Babesiosis

Diagnosis begins with a complete history and a physical exam. Your veterinarian will most likely do the following:

History - If they suspect babesiosis, your veterinarian will likely inquire about tick exposure and bite history.
CBC/Chemistry Panel - These blood tests will evaluate various internal organ functions, including the heart, liver, kidneys, pancreas, metabolism, and electrolyte balance. The CBC is a measure of the amount and different kinds of red and white blood cells that are present in your cat’s body. Your veterinarian will likely be looking for elevated ALT levels, which is an enzyme that is released into the blood when the liver is diseased or damaged. Levels of total bilirubin, a byproduct of red blood cell breakdown, may also be elevated. Other levels on the blood work will usually remain within normal ranges.
Blood smear - This technique is used to examine the individual cells in your cat’s blood. Your veterinarian will use a drop of blood from your cat’s leg or neck and spread it thin in a slide. They will then examine the slide under a microscope in order to see the Babesia parasite.
Immunofluorescence - This is a technique used to illuminate a pathogen or antibodies to a pathogen in a tissue or culture using a fluorescent dye. In this case, your veterinarian will make a tissue or cell smear and expose it to a specific antibody for babesiosis. The dye will attach to any Babesia antibody displayed in the sample and show under a microscope as a bright green spot on the slide.

Treatment for Feline Babesiosis

Most drugs that are effective against Babesia in other animals will not be effective against Babesia felis. Your veterinarian will likely prescribe injections of primaquine phosphate, an anti-malarial, to treat the infection. Other drugs such as doxycycline are more cost effective and may also be effective.

Cats infected with this disease are often lifetime carriers able to infect ticks even after symptoms have gone away. Symptoms may recur if your cat becomes stressed and its immune system allows the protozoa to get out of control again.

Prevention of Feline Babesiosis

While it is still not known for sure how feline babesiosis is transmitted in cats, it may be prevented by reducing the number of ticks that bite your cat. This may be achieved by:

Regularly use a flea preventive that protects against ticks as well.
Avoid environments frequented by ticks (especially between May and August, though ticks can be active in any temperature above 32°F) and check your cat for ticks after they go outside.

Proper removal of ticks

Removing ticks within 24 hours of exposure can greatly reduce the chance of your cat getting babesiosis. Ticks do, however, carry many other pathogens and frequent checks and proper removal are crucial to the prevention of disease. If the ticks stay on your cat long enough to get a full blood meal, they will often release themselves and fall off your cat unnoticed.

Use fine point tweezers to remove the tick at the mouthparts or as close to the skin as possible. Tricks like using petroleum jelly, alcohol, or a match will not cause the tick to back out and may even cause it to regurgitate more bacteria into your cat. Make sure you pull the mouthparts out slowly and steadily. If you do not remove the head of the tick, it can continue to regurgitate fluid into your cat, potentially transmitting the bacteria causing babesiosis. Disinfect the wound on your cat. A triple antibiotic ointment may help the wound heal faster. After removal, be sure you kill the tick by putting it in a jar of alcohol (this may also help with identification, if need be later). Flushing the tick down the toilet will not kill it. Because you likely removed it before it had a full meal, the tick will usually look for another host to feed on, and if it’s a carrier, it can transmit the bacteria to others.