Feline hemoplasmosis (formerly called hemobartonellosis) is an infectious anemia caused by Mycoplasma haemofelis and related species that parasitize red blood cells. Signs range from mild lethargy and pale gums to acute collapse from severe anemia. Cats co-infected with feline leukemia virus (FeLV) or FIV are at greatest risk for life-threatening disease. Prompt diagnosis and antibiotic treatment typically lead to recovery.
Last reviewed: June 2026
What Is Feline Hemoplasmosis?
Hemoplasmas are obligate intraerythrocytic (red-blood-cell-dwelling) bacteria of the class Mollicutes. Mycoplasma haemofelis (large form) causes the most severe clinical disease; Candidatus Mycoplasma haemominutum is more common but typically causes subclinical or mild anemia. Infection occurs via blood-sucking ectoparasites (fleas, ticks), cat bites, and possibly blood transfusions. As described in Ettinger's Textbook of Veterinary Internal Medicine, the bacteria attach to the surface of red blood cells, triggering immune-mediated destruction — so the anemia is partly infectious and partly immune-mediated in nature.
The AAFP Feline Retrovirus Guidelines, 2020 note that FeLV- and FIV-positive cats are significantly more likely to develop severe, life-threatening anemia from hemoplasma infection because their immune systems cannot mount effective responses to control both the retroviral infection and the hemoplasma parasitemia simultaneously.
Signs of Feline Hemoplasmosis
Clinical severity varies with the causative species, the cat's immune status, and whether a concurrent immunosuppressive condition is present. Mild infections may produce only subtle signs detected only by blood work.
Common signs:
- Lethargy and weakness — often the first and most prominent sign
- Pale, white, or slightly yellow (icteric) gum color
- Decreased or absent appetite
- Weight loss in chronic cases
- Rapid or labored breathing (compensatory tachypnea from anemia)
- Weakness or reluctance to move
- Cold extremities (in severe anemia from poor peripheral perfusion)
- Fever (variable — present in acute phase, may be absent)
- Splenomegaly (enlarged spleen, sometimes palpable)
Severe cases may present with collapse, open-mouth breathing, and cardiovascular shock — all reflecting the body's inability to compensate for profound anemia.
Diagnosis
A complete blood count (CBC) revealing regenerative or non-regenerative anemia (often with hematocrit below 20%) raises suspicion. Blood smear examination may reveal hemoplasmas as small dark dots or chains attached to erythrocytes, but sensitivity is low (≤50%) and varies by lab expertise. PCR testing on EDTA whole blood is the most sensitive and specific diagnostic method and differentiates M. haemofelis from Candidatus M. haemominutum. All cats diagnosed with hemoplasmosis should be tested for FeLV and FIV.
Treatment
Doxycycline (5–10 mg/kg/day orally for 4–6 weeks) is the first-line antibiotic — it does not clear the organism completely but reduces parasitemia to subclinical levels in most cats. Marbofloxacin is an alternative. Prednisolone is often added at immunosuppressive doses to blunt immune-mediated red cell destruction, particularly in severely anemic cats. Whole blood or packed red blood cell transfusion is life-saving in cats with hematocrit below 12–15%. Most cats respond within 1–3 weeks of treatment, though subclinical carrier status may persist.
When to See a Vet
Call your vet today if:
- Your cat's gums look pale, white, or yellowish
- Your cat is unusually lethargic and won't eat for more than 24 hours
- Your cat is breathing more rapidly than normal at rest
Go to the ER immediately if:
- Your cat is open-mouth breathing or gasping
- Your cat collapses or cannot stand
- Your cat's gums are grey or white and they are cold to the touch
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Frequently Asked Questions
How do cats get hemoplasmosis? The primary transmission route is through blood-sucking ectoparasites, especially fleas. Cat bites (common during fighting in outdoor cats) are also an important route. Year-round flea prevention and keeping cats indoors reduces exposure significantly.
Can hemoplasmosis be cured? Doxycycline reduces parasitemia to undetectable levels in most cats within 4–6 weeks, but many cats remain subclinical carriers long-term. True sterile clearance is uncommon. Cats that recover and are immunosuppressed later (by illness, medication, or concurrent retroviral infection) may relapse.
How much does treating cat anemia from hemoplasmosis cost? An initial workup (CBC, blood smear, PCR, FeLV/FIV testing) typically runs $250–$500. Doxycycline treatment costs $30–$80 per month. Blood transfusion, if needed, adds $400–$800 per unit. Hospitalization for severely anemic cats runs $400–$1,200 per day. Total treatment cost ranges from $500 for mild cases to $3,000+ for severe cases requiring transfusion and hospitalization.
Is hemoplasmosis contagious to other cats in the household? Not directly by casual contact. Transmission requires blood transfer — through fleas, cat bites, or shared needles/blood collection equipment. Treating all cats in the household with flea prevention is advisable, and any cat with documented infection should be monitored for potential transmission via fighting if they go outdoors.
Can humans get hemoplasmosis from cats? Human hemoplasmas exist (Candidatus Mycoplasma haemohominis, M. ovis), but documented cat-to-human transmission of feline hemoplasmas is extremely rare and typically affects severely immunocompromised individuals. Routine precautions (flea control, avoiding cat bites) are appropriate but this is not a major public health concern for healthy individuals.
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