Infectious Anemia in Cats

Hemoplasmas (formerly known as hemobartonella) are a specialized type of bacteria that attack red blood cells, which can cause anemia (a low red blood cell count). Spread most often by external parasites that feed on blood (fleas, ticks, lice or mosquitoes) or by fighting with infected cats means this illness is most common in cats that spend time outdoors. This disease can be difficult to diagnose and when severe, can cause life threatening anemia that requires hospitalization, antibiotic therapy and blood transfusions. 

What Is Feline Infectious Anemia?

Feline infectious anemia is anemia that is caused by a group of bacteria called the hemotrophic mycoplasmas. There are three species that can infect cats (Mycoplasma hemofelis, Mycoplasma haemominutum and Mycoplasma turicencis). Mycoplasma hemofelis causes the most severe form of this disease.  

The organism attacks the outside of the red blood cells. When the body identifies these damaged cells, the immune system attacks and removes them from circulation. It is the removal of these red blood cells by the immune system that causes the cat to become anemic. 

Lethargy: The decreased oxygen in the blood means there is less energy for the cells so the cat is sleepier.

Increased heart rate: The heart rate increases in an effort to get oxygen to the cells that need it.

Increased breathing rate: The breathing rate increases to bring more oxygen into the body.

Pale gums: The gums may be pale due to a decrease of oxygen in the blood.

Decreased Appetite and Weight Loss: When we don't feel well, our appetite decreases. This is often the case with cat's that are sick as well. Since this infection lasts for a long time, repeated bouts of illness can cause the cat to lose weight.

Fevers that come and go: Most cats will carry the organism in their blood fighting it off until times of stress. Since it stays in the blood long term when the immune system is battling an increased number of organisms the cat will have a fever. Once the number of organisms decreases to a lower number the fever will go away.

Healthy cats may show no signs of illness because they have a low number of organisms that their immune system can control (these cats are called carriers). However, if these cats experience something stressful like another illness, surgery, pregnancy or starvation they may begin to show signs of the disease.

Causes of Feline Infectious Anemia

Cats can become infected in several ways. Most get the infection from external parasites that feed on their blood. These parasites may include fleas, ticks, mosquitoes and lice. The other less common ways for a cat to become infected are being bitten by another cat, receiving a blood transfusion from an infected cat, and during pregnancy from mother to kitten.

Can You Get Feline Infectious Anemia From Your Cat?

No, feline infectious anemia cannot be transferred from a sick cat to a healthy person. There has been a single documented case of a possible transfer from a sick cat to a person that was immunocompromised, but this is very uncommon.

How Is Feline Infectious Anemia Diagnosed?

Feline infectious anemia can be difficult to diagnose. Once a veterinarian has diagnosed a pet with anemia (a low red blood cell count) they may run the following tests looking for the organisms.

• Blood Smear: A drop of your cat’s blood is smeared onto a slide and stained. The veterinarian then looks at the slide using the high-powered lens of a microscope. The organism is only found this way in approximately 50% of infected cats, therefore a negative test does not mean that cat is not infected.
• Polymerase Chain Reaction (PCR) Assay: this is the test of choice for diagnosing feline infectious anemia. This test looks for DNA of the mycoplasma organisms and can differentiate between which of the three organisms is causing the infection. This test is sent to an outside laboratory and can take several days for results.

If your veterinarian suspects that your cat has feline infectious anemia that will also recommend testing the cat for feline leukemia and feline immunodeficiency viruses (FeLV / FIV). It has been documented that approximately 40 to 50 percent of cats with feline infectious anemia are positive for one of these viruses as well.

Treatment of Feline Infectious Anemia

Cats with mild anemia and only a few signs of illness may be treated at home using oral antibiotics and / or steroids to decrease the removal of red blood cells by the immune system.  

Those that are more severely affected will need to be hospitalized so they can receive on IV fluid therapy, steroids to stop the immune system from destroying red blood cells, and / or blood transfusions.

How to Prevent Feline Infectious Anemia

Use parasite prevention to control fleas / ticks / lice and mosquitoes for your cat year round. Keep your cat indoors or only allow them access to outside with direct supervision to prevent fighting. Have your cat tested for FeLV / FIV if they spend any time outdoors or have had cat bite injuries in the past.