Background: Veterinary surveillance for Anaplasma and Ehrlichia spp. in dogs is essential to assess human exposure risk. Annual testing is recommended in endemic regions of North America.
Objective: Compare the performance of screening tests for Anaplasma and Ehrlichia spp. antibodies in canine serum, plasma, or whole blood to an indirect fluorescent antibody test (IFA - REFERENCE) for A. phagocytophilum, A. platys, E. canis, E. chaffeensis, a species-specific ELISA test for E. ewingii and a commercial in-hospital test (SNAP® 4Dx® Plus, IDEXX).
Animals: Anonymized (IFA-characterized) remnant serum samples (n = 786; Anaplasma spp. n = 358, Ehrlichia spp. n =428) were obtained from veterinary reference laboratories and included client-owned dogs.
Methods: Samples were processed (Anaplasma spp. n = 220, Ehrlichia spp. n =200) using the following tests to evaluate the performance metrics: 1. trūRapid FOUR® (Antech Diagnostics, Mars Petcare Science & Diagnostics, 3. IFA (REFERENCE), and 4. species-specific in-house ELISA test for E. ewingii. Kappa statistics was calculated to evaluate test agreement between trūRapid FOUR® and SNAP4Dx® (Anaplasma spp. n=138, Ehrlichia spp. n=228).
Results: Table 1 shows performance metrics for trūRapid FOUR® using REFERENCE as standard and Kappa agreement between trūRapid FOUR® and SNAP4Dx®. The lower agreement for trūRapid FOUR® in Ehrlichia testing with SNAP4Dx® is due to SNAP4Dx’s low specificity observed compared to REFERENCE test.
Clinical Importance: The trūRapid FOUR® is an accurate option for in-house Anaplasma and Ehrlichia spp. antibody detection in dogs. This work offers veterinary teams essential clinical information on tick-borne pathogen diagnostics to support One Health.
