Cat Feline Infectious Anaemia: Welfare and Treatment

Feline infectious anaemia (FIA), caused by Mycoplasma haemofelis and related species, causes haemolytic anaemia and significant welfare compromise in infected cats.

Key Facts

FIA is caused by haemotrophic mycoplasmas that attach to red blood cells, causing immune-mediated destruction
Transmission occurs through bites from infected cats, and possibly through fleas and ticks
Clinical signs include lethargy, pallor, weight loss, and in severe cases collapse from profound anaemia
Treatment with doxycycline eliminates active infection, but some cats remain carriers
Outdoor cats and cats with concurrent FIV or FeLV infection are at highest risk of severe disease

Welfare Considerations

FIA causes significant suffering through the progressive effects of haemolytic anaemia — weakness, breathlessness, reduced consciousness, and profound malaise from inadequate oxygen delivery to tissues. Severely affected cats may require blood transfusions alongside antibiotic treatment to survive the acute phase. The treatment response to doxycycline is often marked, with rapid clinical improvement as mycoplasma load declines and red cell destruction reduces. Cats that survive the acute phase may relapse under stress or immunosuppression. The welfare case for strict flea and tick control is compelling — reducing vector transmission prevents a seriously welfare-compromising disease.

What You Can Do

Maintain strict flea and tick prevention in cats, particularly those with outdoor access
Seek prompt veterinary assessment for cats showing rapid development of lethargy, weakness, and pallor
Complete the full antibiotic treatment course and retest for mycoplasma clearance after treatment
Monitor cats with resolved FIA during periods of stress or illness for signs of relapse