Comparison of two diagnostic methods for Dirofilaria immitis: modified Knott test and ELISA

  Abstract:  Heartworm disease caused by Dirofilaria immitis, affect canine and human population. Distribution of the diseases is worldwide, however endemic in temperate, tropical and sub tropical zones. Adult heartworm infection can be diagnosed with blood tests that detect circulating microfilariae or adult antigens. To evaluate the efficacy of common diagnostic tests of Dirofilariosis, in this study the rate of infection to Dirofilaria immitis were evaluated In 350 dogs in studied area, using a commercial ELISA kit (Anigen co.) for detecting circulating antigen and modified Knott test for detecting microfilariae.   Out of 350 blood samples, 52 (14.8%) samples with ELISA kit and 42(12%) samples with modified Knott tests were positive. In this study, 12 samples were positive when ELISA applied but they were negative with Knott test, while 2 positive samples in Knott test had not reaction in other test. In statistical analysis, the Kappa value between these two test were calculated as 0.83 (p=0.0005) showing good consistency of these two tests.