Evaluation of diagnostic procedures for detection of mycoplasmal pneumonia of swine.

The complement-fixation test (CFT), a latex-agglutination test (LAT), and Mycoplasma hyopneumoniae isolation procedures were compared with gross and microscopic lung evaluations for the routine diagnosis of mycoplasmal pneumonia (MP) of swine. The difficulty and variability of M hyopneumoniae isolation rendered this technique unacceptable. In market-weight swine, the finding of typical gross lesions was correlated with CFT results (P less than 0.005). The MP status of a herd could not be determined by use of these techniques in 4- to 9-week-old pigs. No technique could be used alone to establish a diagnosis. Gross and microscopic examination of all slaughter specimens, CFT, and clinical evaluation of the herd, used in combination, were the most useful means of determining the MP status of the herd.