The immunoperoxidase technique as an auxiliary method for the detection of Mycoplasma hyopneumoniae in naturally infected pigs was evaluated. Eighty lung fragments of which 40 from animals of farms considered negatives and 40 of farms with positive diagnosis of enzootic pneumonia were collected. The results obtained with polyclonal specific serum (IgG of rabbit anti - M. hyopneumoniae) evidentiated a positive correlation of 77% between microscopic and immunohistochemical diagnoses, while the correlation between the macroscopic and immunohistochemical diagnoses was of 49%. In the farms considered negatives the presence of discrete immunoreaction in 22.5% of the cases, what could indicate the existence of cross reaction with other microorganisms, was observed. In the farms with positive diagnosis for enzootic pneumonia the peroxidase-anti peroxidase technique revealed different degrees of intensity, varying from weak immunomarcation to thick brownish deposit in the epithelium or in the light of the airways, or still inside macrophages, with a direct relationship among the intensity of the lesions and the immunoreaction. It was also verified that the immunohistochemistry technique presented 95% of sensibility and 77.5% of specificity, being recommended as auxiliary, fast and of low cost tool for the diagnosis of swine enzootic pneumonia in routine laboratories of histopathology.
swine; immunohistochemistry; enzootic pneumonia; Mycoplasma hyopneumoniae
