Ixodes scapularis, the black-legged tick, is the vector for Anaplasma phagocytophilum and Borrelia burgdorferi in the eastern and midwestern United States.5 While little is known about these infections in cats, some clinically ill, client owned cats have had A. phagocytophilum DNA amplified from blood and have apparent clinical responses to tetracycline administration. Antibodies against B. burgdorferi have been detected in serum from some client-owned cats.
The purpose of this study was to allow wild-caught I. scapularis to feed on healthy research cats (n = 4) and evaluate for A. phagocytophilum DNA in blood by a polymerase chain reaction (PCR) assay as well as for antibody responses. Cats were infested with wild-caught I. scapularis for 7 days. Genomic DNA of A. phagocytophilum was amplified from the blood before antibodies were detected in all 4 cats. Antibodies against the Lyme organism and Anaplasma were detected in the sera of all 4 cats. The results suggest that a PCR assay should be considered in acutely ill cats with suspected anaplasmosis that are seronegative for antibody. (MK)