Introduction

Rhipicephalus sanguineus ticks are prevalent in South East Asia, transmit protozoal and bacterial pathogens in dogs. Of these pathogens, Ehrlichia canis, the causative agent for canine monocytic ehrlichiosis (CME), is most frequently associated with marked clinical manifestations in dogs. Chronic infections are also common. Diagnosis of CME is generally accomplished by hematologic and serologic findings. Conventional serological tests include immunofluorescence assay (IFA) and ELISA. Rapid in-clinic tests are also commonly used in Asia, including SNAP® 4Dx® Plus (IDEXX) and Anigen CaniV-4 (BioNote). Their relative performance has not been validated.

Objectives

To evaluate SNAP® 4Dx® Plus and Anigen CaniV-4 for detection of antibodies to E. canis in dogs from Bangkok, Thailand.

Methods

Client-owned dogs were brought for a spay-neuter program and blood parasite diagnosis through mobile veterinary academic services. The remaining plasma samples from the program stored frozen were used. Majority of the dogs had access to outdoors and had evidence for tick or flea infestation. E. canis IFA testing was performed by a commercial reference laboratory. A total of 57 positive (IFA titer ≥1:100) and 41 negative samples were included in this study. Samples were blinded and randomized for testing with rapid in-clinic tests, according to manufacturers’ instructions.

Results

Compared to E. canis IFA, sensitivity/specificity was 94.7%/100% for 4Dx® Plus, 63.2%/100% for CaniV-4.

Conclusions

This study revealed significant performance differences between the two in-clinic tests. The 4Dx® Plus test may be better suited for rapid and accurate diagnosis of E. canis infection in this region.