Some observations on experimentally induced infection of dogs with Babesia gibsoni.

Splenectomized andnonsplenectomized dogs were experimentally infected with Babesia gibsoni. Infectivity of parasites was retained for 1 month in samples of blood kept at 4 C in a mixture with Alsever's, acid-citrate-dextrose (ACD), or ammonium-potassium oxalate solutions. When samples were slowly frozen to -70 C in a mixture with citrate solution, the parasites remained infective for 4 months. The average prepatent period was 3.3 days in splenectomized dogs and 4 days in nonsplenectomized dogs. Clinical signs were mild fever and anemia in nonsplenectomized dogs and fever, anemia, icterus, and rarely, hemoglobinuria in splenectomized dogs. Blood packed cell volume (PCV) decreased to as little as 11%, and total bilirubin increased to as great as 0.85 mg/dl. Latent parasitemia was still detectable in some dogs 135 days after the initial parasitemia. Gross pathologic changes mainly involved liver and spleen. Hepatic degeneration was always present.