Respiratory disease induced by Mycoplasma hyopneumoniae (Mhyo) is a problem recognized by the swine industry world-wide. Due to the significant production costs associated with Mhyo-induced respiratory disease, eradication is a strategy of interest to many producers. To implement a successful eradication strategy for an organism, effective diagnostic assays capable of accurately detecting infected animals is critical. The purpose of this study was to investigate the ability of common diagnostic assays to detect of Mhyo infection. Of special interest was determining the ability of serological assays to detect early infection. Also investigated was the ability of current polymerase chain reaction (PCR) assays to detect different Mhyo isolates.
A collection of isolates of Mhyo, M. flocculare, M. hyorhinis, and M. hyosynoviae was used to determine if previously published PCR assays were able to correctly detect their targets. In addition, pigs were infected with isolates of common swine mycoplasmas including Mhyo, M. flocculare, M. hyorhinis, and M. hyosynoviae. From these pigs the ability of serum antibody assays (ELISAs) and PCR assays to identify infection with the various isolates was investigated.
All assays were specific for Mhyo and did not detect either antibodies to or DNA from the other swine mycoplasmas. However, the ability of the assays to either detect serum antibodies or DNA varied between the Mhyo isolates. Based on the results of this study a combination of diagnostic assays may be required to accurately assess Mhyo infection under field conditions. Improved diagnostics are needed to accurately assess Mhyo infection status. The need for these diagnostic assays increases with the interest in eradication of Mhyo. Careful interpretation of lab results is required for accurate diagnosis of the infection status of a herd in relation to Mhyo.