Babesiosis: Cats

(Feline Babesiosis)

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Babesiosis in dogs

Babesiosis in horses


Clinical Signs & Symptoms:

Feline Babesiosis generally presents as a chronic, low-grade disease.

  • Lethargy (weakness / loss of energy)
  • Rough haircoat
  • Pyrexia – uncommon (fever)
  • Haemolytic anaemia (anaemias caused by the destruction of red blood cells)
  • Mucous membrane pallor
  • Haemoglobinuria (dark red, haemoglobin-containing urine)
  • Icterus – uncommon (Jaundice – yellowing of the skin and eyes that is caused by too much bilirubin in the blood)
  • Depression
  • Anorexia (loss of appetite leading to weight loss)
  • Tachycardia (rapid heart rate)
  • Tachypnea (rapid breathing)
  • In severe cases: pulmonary oedema, hepatopathy (disorder of the liver), and central nervous system dysfunction

Mucous membrane pallor due to anaemia

Many clinical signs are secondary to haemolytic anaemia that results from intraerythrocytic infection by the piroplasms. Cats generally adapt to the anaemia and may only have mild clinical signs until they are stressed. Concurrent infection withMycoplasma haemofelisFeline Leukaemia Virus (FeLV), or Feline Immunodeficiency Virus (FIV) may contribute to the clinical presentation and severity of disease.

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Diagnostic Tests

Serology cannot be used reliably in domestic cats because reference intervals for babesiosis-related serologic titers have not been established.

Identifying intracellular piroplasms within erythrocytes on a Romanowsky or Giemsa-stained peripheral blood smear can be difficult as small piroplasms can be morphologically indistinguishable and the level of parasitemia may be low. Subsequently, the best strategy for definitive diagnosis of intraerythrocytic piroplasms is by molecular methods.

Polymerase Chain Reaction (PCR) detection of Babesia spp. DNA is a useful technique to document infection in a blood sample.

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A variety of experimental drugs have been used to treat experimental infections of B. felis in domestic cats. Trials have provided variable and questionable results. Studies have also suggested that repeated or chronic antiprotozoal therapy may be necessary to effectively treat feline Babesiosis.
Blood transfusion may be required in severe cases of anaemia.

Note for veterinarians: For a more exhaustive list of potential antiparasitic drugs, consult table 77-3 in Greene’s Infectious Diseases of the Dog and Cat.

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Currently an effective vaccine is not commercially available to protect cats against Babesiosis.

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Further Information

Babesiosis in Dogs

Babesiosis in Horses

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