Mycoplasma ovipneumoniae

Mycoplasma ovipneumoniae is a species of Mycoplasma bacteria that most commonly inhabits and affects ovine animals. M. ovipneumoniae is a respiratory pathogen of domestic sheep, domestic goats, bighorn sheep, mountain goats, and other caprinae that can both cause primary atypical pneumonia and also predispose infected animals to secondary pneumonia with other agents, including Mannheimia haemolytica. Several mechanisms are involved in the pathogenicity of M. ovipneumoniae, including altering macrophage activity, adhering to the ruminants' ciliated epitheluim via its polysaccharide capsule, inducing the production of autoantibiodies to cilary antigens, and suppressive activity on lymphocytes, all of which are important factors that contribute to the disease in sheep and other small ruminants. The bacterium also has the ability to act as a prediposing factor for other bacterial and viral infections.

Populations of M. ovipneumoniae of infected sheep are often found to have varying strains of the bacterium within one animal, but the different strains vary in virulence. The bacterium can be found within the lungs, trachea, and nasal cavity of small ruminants. However, the detection of M. ovipneumoniae can be obtained by bacteriologic culture, molecular dignosistics, and serology, allowing for the bacterium to be grown in culture, species-specific DNA sequences, and specific antibiodies identified, respectivitly.

In July 2007, this species of Mycoplasma was linked to the deaths of bighorn sheep in the Western United States. M. ovipneumoniae is also a predominant bacterium associated with broncopneumonia lesions in free-ranging bighorn lambs. Introductions come from either domestic sheep and goats (which harbour M. ovipneumoniae with limited morbidity), or through contact with other infected bighorn sheep which survived initial infection events to become long-term chronic carriers. Once a bighorn population is infected with M. ovipneumoniae, the pathogen is difficult to eliminate, and is associated with stagnant-to-declining population growth rates. M. ovipneumoniae is also associated with population declines in several other wild caprinae, including the Norwegian muskox. Mycoplasma species are labile organisms which are easily destroyed by heat, dehydration, sunlight, and common disinfectants, so they do not survive for a long time outside the body of the animal. As of now, and with many Mycoplasma diseases, no protective immune responses have been achieved with the use of vaccines, though antibodies can be obtained.