Objective: To evaluate the prevalence of, and laboratory abnormalities associated with, canine babesiosis.

Design: 2,117 dogs admitted to the National Taiwan University Veterinary Hospital as first opinion cases between January 1998 and December 1999 were studied.

Materials and Methods: Complete blood counts, blood smears stained with Liu's stain, and routine blood biochemical profiles were carried out in dogs presented with a history of tick infestation and manifesting pale membranes.

Results: The overall prevalence of babesiosis was 1.75% prevalence of Babesia gibsoni and Babesia canis infections was 1.56% and 0.19% respectively. Maltese Terriers showed a breed predilection to babesiosis (p < 0.05). Anemia (83.8%) with regeneration (60.1%), eosinopaenia (59.3%), monocytosis (27.0%) and leukocytosis (24.3%) were the major abnormalities in the hematological profile. Elevated ALT (37.5%), hypoglycaemia (30.4%) and elevated ALKP (25.0%) were the major abnormalities of biochemical parameters. Over 40% of the cases were admitted in the autumn.

Conclusions: Babesia gibsoni was the predominant babesia in this area. A regenerative anemia was the major finding of dogs affected with babesiosis. Maltese Terriers showed a breed predilection to infection.