Infectious Anemia in Cats 🐱🩸

By Dr Duncan Houston, BVSc

Infectious anemia in cats—also known as feline hemotropic mycoplasmosis—is caused by a group of red blood cell–attacking parasites known as Mycoplasma haemofelis, M. haemominutum, and M. turicensis. These microscopic invaders can trigger life-threatening anemia and are often overlooked until symptoms become severe. 😿

🦠 What Is It?

Mycoplasmas are bacteria that live on red blood cells, feeding off them and marking them for destruction by the immune system. As red cells are removed, the cat becomes anemic. This group of diseases used to be called feline infectious anemia, but today we recognize several distinct mycoplasmas and understand their impact more clearly. 🧬

🩺 How Infection Happens

Most cats become infected through:

• 🦟 Flea bites (most common)
• 🩸 Blood transfusions (rare)
• 🐾 Possibly from mothers to kittens
• 😾 Possibly through bite wounds (still unconfirmed)

At-risk cats include:

• 😾 Outdoor roamers
• 🧔‍♂️ Intact males
• 🐈‍⬛ Cats <4–6 years old
• 😿 Cats with FeLV (Feline Leukemia Virus) or weak immune systems

📋 What Happens to Infected Cats?

The parasite attaches to red blood cells. Once detected, the immune system marks these cells for destruction. In severe cases, so many red cells are destroyed that the cat becomes weak, pale, and even jaundiced. 😰

Typical symptoms:

• 🩸 Pale gums
• 🐢 Lethargy
• 🌡️ Fever
• 🧺 Eating litter or dirt (due to iron craving)
• 💩 Jaundice or yellowing skin

Cats with FeLV may experience bone marrow failure, and the anemia is often more severe. Infection takes 2–4 weeks to reach peak impact. Carrier cats can relapse under stress. 🔄

🔬 Diagnosing Hemotropic Mycoplasma

These bacteria can’t be cultured like typical infections. Diagnosis relies on:

• 🧫 Blood smear microscopy (but detection varies hourly)
• 🧬 PCR test – detects DNA from Mycoplasma and identifies the species (best test)
• 🩺 Full blood panel – reveals anemia and immature red blood cells

PCR testing is most accurate when done early and before antibiotic treatment begins. Peak detection occurs 2–4 weeks post-infection. 🔍

💊 Treatment Plan

Early treatment is lifesaving. If your vet suspects mycoplasma, they may begin therapy before test results return.

Medications include:

• 💊 Doxycycline (preferred antibiotic, compounded liquid is safest)
• 💊 Enrofloxacin or other quinolones as second-line options
• 💉 Prednisolone to reduce immune destruction of red cells
• 🩸 Blood transfusion for severely anemic patients

Three weeks of antibiotics are typically prescribed. Carrier cats are not usually treated unless they are sick, FeLV+, or immunosuppressed. 🧾

📈 Prognosis

With timely diagnosis and proper antibiotics, most cats recover quickly and fully. The prognosis is fair to good, especially if treatment is started early. Cats with FeLV or severe anemia may have a more guarded outlook. 💉

🛡️ Prevention

Preventing Mycoplasma infections comes down to flea control and health maintenance:

• 🦟 Use flea preventives consistently
• 🩺 Test for FeLV and FIV regularly
• 🐈 Keep indoor cats separate from known outdoor fighters
• 🩸 Use only screened blood for transfusions

Carrier cats are not contagious if fleas are well controlled. 👍

📱 Ask A Vet App Support

Worried about anemia, pale gums, or flea-transmitted illness? The Ask A Vet app can help:

• 🧪 Review PCR or blood test results
• 💬 Confirm treatment protocols and antibiotic options
• 🧾 Get flea prevention product guidance
• 📋 Track symptoms and medication reminders

🏁 Final Takeaway

Infectious anemia in cats is deadly—but treatable. Early diagnosis, proper antibiotics, and supportive care make a huge difference. Control fleas, screen for FeLV, and monitor for signs of fatigue or pale gums. When in doubt, consult your vet—or use Ask A Vet for expert help right away. 🐱🩺❤️