Rapid Diagnosis of Babesia gibsoni by Point‐of‐Need Testing by Insulated Isothermal PCR in Dogs at High Risk of Infection

BACKGROUND Dogs seized by law enforcement agencies during dogfighting investigations are at increased risk of Babesia gibsoni infection. A rapid and cost-effective diagnostic test would increase the feasibility of mass screening of dogs for infection and monitoring treatment efficacy in B. gibsoni-infected dogs. OBJECTIVE To determine the performance of a point-of-need insulated isothermal PCR (iiPCR) test for diagnosis of B. gibsoni in dogs rescued in dogfighting investigations. ANIMALS Two hundred and thirty-three dogs seized in dogfighting investigations. METHODS Cross-sectional study. Whole blood samples were tested for B. gibsoni and Babesia spp. by iiPCR. Results were compared to a reference standard comprised of concordant results from real-time PCR in a commercial diagnostic laboratory and antibody titers. RESULTS The iiPCR system was quick to learn, portable, and had a short processing time of <2 hours. Sensitivity and specificity of the iiPCR assay for B. gibsoni were 90% (95% confidence interval [CI] 81-95%) and 99% (CI, 95-100%), respectively. Sensitivity and specificity of the iiPCR assay for Babesia spp. were 87% (CI, 78-93%) and 98% (CI, 0.94-99%), respectively. CONCLUSIONS AND CLINICAL IMPORTANCE The iiPCR system produced few false-positive results, indicating that positive results are likely to represent true infections when used in high-risk animals. The iiPCR system can fail to identify 10-15% of truly infected dogs. However, the portability, speed, and economy of the iiPCR system compared to testing through a reference laboratory can allow rescue groups to screen and identify infection in more dogs.