Mycoplasmal pneumonia is commonly referred to as “enzootic
pneumonia,” meaning that the disease is widespread and common
among a population of animals.  There have been many estimates
of prevalence within the U.S. swine industry, but most would
agree that well over 90% of swine herds are positive for this
organism.  The mycoplasma organism is a very small bacterium
without a cell wall. It is a unique pathogen in that it does not
invade the body, but instead colonizes the mucosal surfaces of
the respiratory tract, destroying the surface cells (epithelium)
and villi of the respiratory tract. This process makes the pig
more susceptible to other bacterial pathogens such as
Pasteurella multocida and allows viruses to replicate more
easily.  In turn, the body does not mount an immune response in
the same manner as when confronted with other bacterial
pathogens.  The cell structure and the way it causes disease
makes mycoplasma difficult to treat with many of the commonly
used antibiotics.  Enzootic pneumonia, assoc