Comparison of Microscopy and Multiplex PCR for the Identification of Haemoparasites in Naturally Infected Dogs in Andhra Pradesh

Blood samples from 442 dogs with tick infestation and/or showing clinical signs suggestive of haemoprotozoan and rickettsial infections, presented to private or government hospitals in Andhra Pradesh were examined by microscopy and multiplex PCR. The results revealed presence of Babesia species, Ehrlichia canis and Hepatozoon canis in the dogs in the study area. The overall prevalence of these haemoparasites in dogs was 21.0% (93/442) and 43.4% (192/442) by microscopy and multiplex PCR respectively, indicating a higher prevalence of parasites by multiplex PCR. Significant variation in the prevalence of single species infection and co-infection with more than one haemoparasites (χ2 = 13.517; df=1; P=0.000236) was observed. Ninety-nine samples negative by Giemsa-staining were found positive with at least one haemoparasite by multiplex PCR. The prevalence of ehrlichiosis, hepatozoonosis, and babesiosis in dogs was 9.3, 1.7 and 11.8% respectively, by microscopy and 23.5, 6.1 and 28.3% respectively, by multiplex PCR. Infection with Babesia spp. was found to be more common in dogs in the study area than E. canis and H. canis by multiplex PCR as well as by conventional microscopy.