Mycoplasma hyopneumoniae (MH) is common in Swiss wild boar as detected by RT-PCR. There was little information on enzootic pneumonia (EP) in wild boar until the study in Spain in 2010 which showed that antibodies were detected in 21% of 428 serum samples and in 20% of nasal swabs. MH was detected by nested polymerase chain reaction (nPCR) and in 8% (of 156) of lung samples. No gross lesions were seen in any of the pigs, but histologic lesions were seen in 18 of 63 (29%) of lung samples. The conclusion was that the EP lesions were likely to be subclinical.
It is the cause of mycoplasmal pneumonia of swine, often known as enzootic pneumonia. It is a common, chronic, usually nonfatal disease of young pigs. The disease may be endemic, or spread slowly but progressively through a facility over the course of weeks, and the morbidity rate may be as high as 70-100%. Although pigs as young as 5 weeks of age may develop disease, it is most important in grower-finisher pigs and may be a key component of fatal multifactorial pneumonia in 4- to 6-month-old hogs. Clinical expressions of the uncomplicated disease are coughing, unthriftiness, poor weight gain, and reduced feed conversion. Because there is usually low mortality associated with mycoplasmal pneumonia, the lesions are generally seen in slaughtered animals or those dying from other diseases. When deaths do occur, they are mainly due to superimposed infections with other bacteria.