Immuno-diagnosis of Dirofilaria repens infection in dogs by counter immunoelectrophoresis (CIEP)

Immuno-diagnosis of Dirofilaria repens infection in dogs was attempted by counter immuno-electrophoresis (CIEP) using crude adult worm antigen. A total of two hundred and fifty blood samples of dogs were initially screened for the presence of microfilaria by modified Knott's method. One hundred and thirteen (45.2%) samples were positive for microfilaria. The serum samples collected from the same dogs, when subjected to CIEP with crude adult worm antigen for the detection of circulatory antibodies of D. repens, revealed, 141 (56.4%) to be positive. Among 141 CIEP positive samples, 43 (30.49%) showed clear thick precipitin line and 98 (69.51%) samples showed thin precipitin. Of the 141 samples, while 113 dogs had microfilaria by modified Knott's method, blood samples of 28 did not show any microfilaria to indicate past infection. The sensitivity and specificity of counter immuno-electrophoresis was found 100% and 73.04%, respectively.