Mycoplasmal arthritis

Mycoplasma hyosynoviae and M. hyorhinis are present in most farms and cause arthritis in swine.

Alternative names: Mycoplasma hyosynoviae, Mycoplasma hyorhinis


Most farms are infected but not all show clinical signs. Mycoplasma hyosynoviae and M. hyorhinis live in the upper respiratory tract without causing clinical signs and are transmitted through the respiratory route. They invade joints and tendon sheaths of susceptible animals producing inflammation and lameness.

Mycoplasma hyorhinis clinically tends to occur in swine from 3 to 10 weeks old and Mycoplasma hyosynoviae is present in pigs of more than 3 months. M. hyorhinis, besides causing arthritis can also cause polyserositis and pneumonia.



All ages

  • Clinical signs in gilts start suddenly.
  • They do not want to get up.
  • Lameness.
  • Inflammation of the hock joints.
  • Affected animals suffer pain and only get up for short periods of time.
  • Body temperature may be normal or slightly elevated.
  • Tremor.
  • Polyserositis (only M. hyorhinis).
  • Pneumonia (only M. hyorhinis).


Causes / Contributing Factors

  • The quality of the pen - especially low temperatures and air currents, which act as triggers.
  • Mix of animals and fights, such situations cause stress.
  • High density of animals.
  • Poor ventilation.
  • Slippery or rough floors.



  • It is based on clinical signs and response to treatment. Intra articular fluid can be sucked to examine whether antibodies are present and isolate the organism.
  • Serology is not much help because subclinical infections are common and therefore healthy animals often have antibody titers. However an increase in antibody titer in blood samples taken two weeks apart, along with typical symptoms, suggests the presence of the disease.
  • It may be needed to carry out necropsies to reach a definitive diagnosis. The organisms can be identified through a special culture or PCR.



  • Inject lincomycin, tiamutin, or quinolones.
  • Give strategic medications in feed starting seven days prior to the time that the outbreak is expected to start and continue during 14 days using lincomycin or OTC or CTC.
  • Remember that it is transmitted through the respiratory route and it is necessary to consider other control measures.

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