Dataset for: Doxycycline treatment efficacy in dogs with naturally-occurring Anaplasma phagocytophilum infection

Objectives: To evaluate doxycycline treatment efficacy and post-treatment pathogen persistence in dogs naturally infected with Anaplasma phagocytophilum in endemic regions of the US. Methods: Symptomatic dogs in four US states (MN, WI, CT and CA) were evaluated before treatment with doxycycline and approximately 30 and 60 days post-treatment. Clinicopathological parameters, presence of co-exposures and presence of A. phagocytophilum DNA in whole blood and lymph node samples were evaluated and compared between A. phagocytophilum infected and uninfected dogs. Results: Forty-two dogs fulfilled the inclusion criteria, with 16 dogs (38%) blood PCR positive and 26 dogs (62%) blood PCR negative for A. phagocytophilum. At initial evaluation, the proportion of clinicopathological abnormalities was similar between A. phagocytophilum infected and uninfected dogs, with exception of thrombocytopenia and lymphopenia, which were statistically more prevalent among A. phagocytophilum infected dogs. Treatment with doxycycline resulted in resolution of all clinical abnormalities in A. phagocytophilum infected dogs; 4 dogs had persistent haematological abnormalities, including mild leukopenia, eosinopenia and lymphopenia. All 16 A. phagocytophilum infected dogs became PCR negative in blood approximately 30 and 60 days after treatment onset. Additionally, 13/13 (100%) of lymph node specimens tested post-treatment were PCR negative. Select clinicopathological abnormalities persisted in A. phagocytophilum uninfected dogs after treatment. Clinical Significance: The results of this study support the efficacy of doxycycline therapy for clinical treatment of dogs naturally infected with A. phagocytophilum in the US. This study did not find clinical, haematologic or microbiologic indicators that supported the persistence of A. phagocytophilum infection in naturally infected dogs following treatment with doxycycline for 28 days.