Hemotropic Mycoplasmosis (Feline Infectious Anemia)

Overview

An infection with Mycoplasma organisms that attach to red blood cells, causing the immune system to destroy these infected cells and resulting in anemia — genuinely one of the more commonly recognized infectious causes of feline anemia, transmitted primarily through flea bites or cat bite wounds.

Symptoms

• Lethargy (moderate, common)
• Pale/white gums (severe, common)
• Decreased appetite (moderate, common)

Causes

Infection with Mycoplasma haemofelis or related Mycoplasma species that attach directly to the surface of red blood cells, marking these cells for destruction by the immune system as it attempts to clear the infection. Caused by Mycoplasma organisms that attach to and damage red blood cells, this infection (also called feline infectious anemia) is transmitted primarily through flea bites and, less commonly, cat bites — the resulting red blood cell destruction leads to the anemia that gives the condition its clinical name and presentation.

Risk Factors

Flea exposure (a primary transmission route), outdoor access with cat fight/bite wound exposure (another recognized transmission route), and any condition suppressing normal immune function that could allow more significant infection.

Transmission

Primarily transmitted through flea bites, and through bite wounds from cat fights; less commonly through blood transfusion from an infected donor.

Incubation Period

Typically 1-3 weeks following exposure before symptoms become apparent.

Disease Stages & Progression

As the infection causes progressive red blood cell destruction, anemia develops, potentially ranging from mild to severe depending on the extent of infection and the individual cat's immune response, with symptoms reflecting the degree of anemia present.

Early Warning Signs

Lethargy, pale gums, and decreased appetite as anemia develops. Pale gums, lethargy, weakness, and sometimes a rapid heart rate (the body's attempt to compensate for reduced oxygen-carrying capacity from fewer functional red blood cells) are the hallmark signs — cats with a concurrent condition affecting their immune system (like FIV or FeLV) tend to experience more severe disease from this infection than otherwise healthy cats.

Advanced Symptoms

Significant lethargy, notably pale or white gums, weakness, and in severe cases, collapse given how significant the anemia can become.

Diagnostic Methods

PCR testing specifically identifying Mycoplasma haemofelis or related species, combined with evidence of anemia, confirms this diagnosis. A blood smear examined under a microscope can sometimes directly show the organisms attached to red blood cells, though PCR testing is considerably more sensitive and reliable for confirming diagnosis, particularly since the organisms can be present in cyclical waves that a single blood smear might miss.

Veterinary Examination Process

Assessment of gum color and overall status reflecting anemia severity.

Recommended Lab Tests

Complete blood count, PCR testing for Mycoplasma species, blood smear examination.

Diagnostic Imaging

Not primarily diagnostic; blood-based testing is more directly relevant.

Blood Test Indicators

Complete blood count showing anemia; specific PCR testing identifies the Mycoplasma organism's genetic material, providing definitive diagnosis; blood smear examination may occasionally show the organisms directly on red blood cells.

Biopsy / Histopathology

Not applicable.

Differential Diagnoses

Other causes of anemia including other infections and immune-mediated conditions — PCR testing specifically identifies this Mycoplasma infection.

Home Monitoring Guidance

Not a substitute for veterinary evaluation of pale gums or unexplained lethargy.

Veterinary Treatment Options

Antibiotic treatment (typically doxycycline) addresses the underlying infection; supportive care including blood transfusion for severe anemia may be needed in significant cases. Antibiotic treatment (doxycycline is standard) addresses the underlying infection; severely anemic cats may need a blood transfusion as urgent supportive care while antibiotics take effect, since antibiotics alone don't immediately reverse existing anemia even once they begin controlling the infection.

Surgery Requirements

Not applicable.

Recovery Timeline

Typically improves within 2-4 weeks of appropriate antibiotic treatment, though some cats may remain carriers of low-level infection.

Possible Complications

Severe anemia requiring transfusion in significant cases; some cats may become chronic carriers with periodic recurrence, particularly if immune function becomes compromised.

Long-Term Management

Most cats recover well with appropriate treatment; monitoring for recurrence, particularly during periods of stress or immune compromise, is reasonable for cats with a known history.

Prevention

Consistent flea control is the most effective prevention given this parasite's role as a primary transmission route; reducing cat fight exposure through indoor living or supervised outdoor access addresses the other recognized transmission pathway.

Vaccination Availability

No vaccine exists against this infection.

Prognosis

Good with appropriate antibiotic treatment, particularly when identified before anemia becomes severe.

References

American Association of Feline Practitioners (AAFP); International Society for Companion Animal Infectious Diseases (ISCAID).

Medications Used

• Antibiotics (typically doxycycline)
• Blood transfusion for severe anemia

Estimated Treatment Cost by Country

Frequently Asked Questions