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Doxycycline treatment efficacy in dogs with naturally occurring Anaplasma phagocytophilum infection
Author(s) -
Yancey C. B.,
Diniz P. P. V. P.,
Breitschwerdt E. B.,
Hegarty B. C.,
Wiesen C.,
Qurollo B. A.
Publication year - 2018
Publication title -
journal of small animal practice
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.7
H-Index - 67
eISSN - 1748-5827
pISSN - 0022-4510
DOI - 10.1111/jsap.12799
Subject(s) - anaplasma phagocytophilum , doxycycline , medicine , leukopenia , clinical significance , buffy coat , anaplasmosis , gastroenterology , immunology , virology , chemotherapy , biology , antibiotics , tick , microbiology and biotechnology , borrelia burgdorferi , antibody
Objectives To evaluate doxycycline treatment efficacy and post‐treatment pathogen persistence in dogs naturally infected with Anaplasma phagocytophilum in endemic regions of the USA. Materials and 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, co‐exposures and A. phagocytophilum DNA in whole blood and lymph node samples were compared between A. phagocytophilum infected and uninfected dogs. Results In total, 42 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, although thrombocytopenia and lymphopenia were statistically more prevalent among A. phagocytophilum infected dogs. Treatment with doxycycline resulted in resolution of all clinical abnormalities in infected dogs; four dogs had persistent haematological abnormalities, including mild leukopenia, eosinopenia and lymphopenia. All 16 infected dogs became blood PCR‐negative approximately 30 and 60 days after treatment onset. Additionally, 13/13 (100%) lymph node specimens tested post‐treatment were PCR‐negative. Select clinicopathological abnormalities persisted in 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 USA. This study did not find clinical, haematological or microbiological indicators that supported the persistence of A. phagocytophilum infection in naturally infected dogs following treatment with doxycycline for 28 days.