Seroprevalence and risk factors associated with Ehrlichia canis in a hospital canine population

Background: Ehrlichia canis (E canis) infection has been documented in a few small canine case series in Greece. However, there is limited information on the prevalence of exposure to, or the potential risk factors associated with E canis seroreactivity in a large native canine population.

Objectives: The objectives of this study were to evaluate E canis seroprevalence in dogs admitted to a veterinary teaching hospital, and to investigate the potential association between seropositivity and signalment, health status, the serologic assays used, and selected clinical and clinicopathologic abnormalities.

Methods: The medical records of 850 client-owned dogs, tested using three in-office serologic assays, were retrospectively reviewed.

Results: The E canis seroprevalence was significantly higher in sick (54.9%) compared with healthy (33.9%) dogs. Seropositivity differed significantly between the serologic assays used in this study (ImmunoComb vs SNAP 3Dx/SNAP 4Dx). Dogs presenting with bleeding tendencies, anemia, thrombocytopenia, leukopenia, pancytopenia, and hyperproteinemia were more likely to be E canis seropositive, and the median hematocrit (HCT), white blood cell (WBC), neutrophil, and platelet values were significantly lower in seropositive compared with seronegative dogs.

Conclusions: A high E canis seroprevalence was documented in a canine population living in an endemic area. Selected clinicopathologic variables might be useful indicators of E canis exposure and could allow the prioritization of serologic testing in the clinical setting.