[Pulmonary dirofilariasis associated with pleural effusion].

A 61-year-old man was admitted to our hospital because of a long history of productive coughing. A chest roentgenogram and CT scan showed a right-sided pleural effusion. The effusion fluid was blood-stained but showed no cytological evidence of malignancy. Marked eosinophilia was found in blood and in the pleural effusion fluid. Ouchterlony's double-diffusion test done with the patients serum and pleural effusion fluid in agarose showed specific bands toward Dirofilaria immitis antigen, and this specificity was confirmed with an enzyme linked immunosorbent assay inhibition test. The final diagnosis was pulmonary dirofilariasis, and the patient responded to diethylcarbamazine.