RESUMEN
Anaplasma platys, agent of canine cyclic thrombocytopenia parasites exclusively dogs platelets. Its probable vector is the tick Rhipicephalus sanguineus. Among the existent diagnostic methods, the most used include: morulae identification in blood smears; antibody detection by indirect immunofluorescence; or DNA amplification by polymerase chain reaction (PCR). Recently a new commercial ELISA (IDEXX®), capable of detecting A. phagocytophilum antibodies, has been developed. According to the manufacturer it appears to have a serological cross reaction with A. platys which may be used to help in the diagnosis of this agent. The aim of this study was to test serum samples from 16 PCR-positive dogs to A. platys with an ELISA that detects antibodies to A. phagocytophilum, Borrelia burgdorferi and Ehrlichia canis, and antigens of Dirofilaria immitis in order to verify the occurrence of cross reaction between A. platys and A. phagocytophilum. All animals tested negative for A. phagocytophilum, B. burgdorferi, and D. immitis. One animal tested positive for E. canis. Although it's known that A. phagocytophilum presents serological cross reaction with A. platys, the tested animals were negative, once antibodies against A. platys were not detected probably because of the acute phase of the disease.