A retrospective study of ehrlichiosis in 62 dogs from North Carolina and Virginia.

The purpose of this retrospective study is to report the clinical signs, clinicopathological findings, and response to therapy of 62 dogs from North Carolina and Virginia. Ehrlichiosis was diagnosed in all of these dogs, and previous retrospective studies of ehrlichiosis in dogs were used as a basis for comparison. In this study, the clinical signs commonly associated with ehrlichiosis were observed less frequently than in earlier studies, although previously reported laboratory abnormalities were similar. Flow cytometry revealed an inverted CD4:CD8 ratio in 3 of 4 dogs tested. This finding is suggestive of potential immune dysregulation that could predispose infected dogs to additional disease processes. Concurrent diseases were frequently reported and often contributed to death. Response to therapy was variable, with timely, complete recovery reported in only 27% of dogs; a slow, gradual, but complete recovery in 18% of dogs; an incomplete treatment response in 25% of dogs; and a presumed treatment failure in 16% of dogs.