Canine vector-borne diseases (CVBD), including leishmaniasis (CanL), canine monocytic ehrlichiosis (CME) and anaplasmosis, are prevalent in Mediterranean countries, South America, parts of Asia and Africa. Diagnosis of CVBD is generally supported by hematologic and serologic findings. Commonly used serological tests include immunofluorescence assay (IFA) and/or ELISA. Rapid in-clinic tests are also available. The aim of this study was to compare the performance of rapid tests with gold standard IFA and/or ELISA for detection of canine antibodies to Leishmania infantum, Ehrlichia canis and Anaplasma platys.

The rapid tests evaluated included SNAP® Leishmania and SNAP® 4Dx® Plus (IDEXX), Uranotest Leishmania and Uranotest Ehrlichia-Anaplasma (Uranovet). Study samples were collected from IDEXX Reference Laboratories from samples remaining after requested diagnostic testing was completed. These samples were originally submitted by attending veterinarians for detection of Leishmania antibodies using LEISCAN® Leishmania ELISA test, or for detection of E. canis antibodies using E. canis IFA. Positive samples for Leishmania were defined for this study as those with ≥1/160 equivalent titer (converted from OD ratio per manufacturer's instructions), negatives with ≤1/20 equivalent titer. To control for potential cross-reactivity of E. canis IFA, a species-specific ELISA (McBride et al. 2007) was used to confirm E. canis samples. Another species-specific ELISA (Qurollo et al. 2014) was used to identify A. platys samples.

Compared to the respective diagnostic standards, the sensitivities of SNAP and Uranotest were 90.3% and 67.7%, respectively, for Leishmania; 96.2% and 65.4% for E. canis; 83.0% and 48.9% for A. platys. Specificities were high for all test kits.

This study revealed that the accuracy of in-clinic rapid tests for CVBD varies significantly. Consistent with previously published studies (Ferroglio et al. 2007; Marcondes et al. 2011; Miró et al. 2013; Stillman et al. 2014; Rene-Martellet et al. 2015), this study using clinical samples continued to demonstrate the high sensitivity and specificity of SNAP tests for detection of Leishmania, E. canis, and A. platys antibodies.

Disclosures

Disclosures to report
All authors are employees of IDEXX Laboratories, Inc.