Page 543 - Problem-Based Feline Medicine

24 – THE ANEMIC CAT 535

Transmission The organism can be detected in infected macrophages
in bone marrow, spleen, liver, or lymph node aspirates
Bobcats are subclinically infected by Cytauxzoon felis
stained with Wright’s or Giemsa stains.
and so are probably the natural host.
Serologic testing can be used to confirm exposure, but
Transmission occurs from infected bobcats to domestic
is usually not needed clinically
cats by Dermacentor variabilis.
PCR assay has been studied experimentally and may
be available in the future.
Pathogenesis
Transmission of the organism results in clinical illness Differential diagnosis
in 5–20 days.
Any infectious, immune-mediated, or neoplastic cause
Schizonts and macroschizonts form in mononuclear of hemolytic anemia can look similar due to the signs
phagocytes, line the lumen of veins, and obstruct associated with fever and anemia. Identification of the
blood flow through tissues (tissue phase). organism is diagnostic.
Merozoites released from infected macrophages infect
erythrocytes causing hemolytic anemia (erythrocyte Treatment
phase).
Fluid therapy and blood transfusion should be admin-
istered as indicated (see hemobartonellosis).
Clinical signs
Imidocarb administered at 5.0 mg/kg, IM, every 14
Most infected cats are presented for depression. days for two doses or diminazene at 2.0 mg/kg, IM,
every 7 days for two doses are the drugs of choice but
Physical examination usually reveals fever, anorexia,
no treatment is known to be effective.
dyspnea, depression, collapse, icterus, and pale
mucous membranes. Parvaquone, buparvaquone, thiacetarsamide and tetra-
cycline therapy have also been attempted.
Hypothermia develops in some cats preceeding death.
Death is a common sequel, but strains of C. felis that Zoonotic potential and prevention
spontaneously resolve have now been recognized.
Cytauxzoon felis is not known to infect people.
Most cases of cytauxzoonosis are in outdoor cats, but
ticks are generally not identified Tick control should be maintained, and cats in endemic
areas should be housed indoors.
The course of disease is generally 1 week or less in
cats infected with pathogenic strains.
HEREDITARY HEMOLYTIC ANEMIA
Cats infected with non-pathogenic strains may live for (PYRUVATE KINASE DEFICIENCY,
years. OSMOTIC FRAGILITY, PORPHYRIA)

Classical signs
Diagnosis
● Lethargy, anorexia, weight loss.
Regenerative anemia, neutrophilic leukocytosis or
● Pale mucous membranes.
leukopenia, thrombocytopenia or thrombocytosis,
● Young Abyssinian, Somalis, Siamese or
hemoglobinemia, hemoglobinuria, bilirubinemia and
DSH cat.
bilirubinuria are the most common laboratory abnor-
malities, but vary between patients.
Clinical signs
Antemortem diagnosis is based on demonstrating the
ring-shaped erythrocytic phase on thin blood Congenital diseases resulting in hemolysis are rare in
smears which occurs in most cats with acute illness. cats.