In-clinic diagnosis of canine anaplasmosis based on haematological abnormalities and evaluation of a stained blood smear.

OBJECTIVE: Haematological changes, evaluation of a blood smear and seasonal variations may assist in an in-clinic diagnosis of acute anaplasmosis.
MATERIAL AND METHODS: Blood samples from 57 dogs were evaluated. The diagnosis of canine anaplasmosis was confirmed by detection of the microorganism by microscopic examination of a stained blood smear.
RESULTS: Thrombocytopenia was present in 56 dogs (98.2%). Red blood cell count, packed cell volume and haemoglobin values were below the reference interval in 38.6%, 24.5% and 26.3% of affected dogs respectively. Based on reticulocyte counts, a non-regenerative anaemia was present in 78.6% of A. phagocytophilum-positive dogs. Leukopenia, lymphopenia, neutropenia, monocytosis and eosinophilia were present in 35.1%, 66.7%, 10.9%, 5.7% and 15.4% of the dogs respectively.
CONCLUSION: The results demonstrate that together with clinical signs, a tentative diagnosis of canine anaplasmosis can be made based on typical haematological changes. The most common haematological abnormalities in dogs affected by canine anaplasmosis were a thrombocytopenia and a lymphopenia; most cases of anaemia were non-regenerative.