Exertional or Capture Myopathy
Risk Factor
  • Exertional or capture myopathy (disease of the muscle) is a non-infectious disease of muscles that is characterized by damage to muscle tissues brought about by physiological changes, usually following extreme exertion, struggle and/or stress.
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Exertional Myopathy Exertional Myopathy
Exertion myopathy evident in leg muscle of a pronghorn antelope. Light colored leg muscle of a sandhill crane represents exertion myopathy.
  • The potential for this condition can occur anywhere animals are pursued or trapped.
  • All year. Warm weather can exacerbate this condition.
Species Affected
  • Both mammals and birds of all ages and sexes are susceptible to this disease.
  • Species differ in their susceptibility to exertional myopathy because of physical and behavioral attributes. It is most commonly seen in wild ungulates in British Columbia.
Mechanisms of Action / Signs and Symptoms
  • Signs vary depending on species, cause of exertion and the types of biochemical imbalances that lead to muscular damage. It may be seen peracutely (immediately), acutely (within minutes or hours) or chronically (days or weeks).
  • Early signs include increased breathing and heart rates, increased body temperature, or sudden death.
  • Additional signs include: depression, muscle stiffness, weakness, tremors, incoordination, or shock, which may appear within hours to days following severe exertion. If the animal survives, residual signs may last as long as a month.
  • Urine of affected animals may be red to brown because of broken down components of muscle moving through the kidneys.
  • Animals that do not initially die may be predisposed to kidney failure, predation and accident.
  • Muscles may appear pale and wet or very dark red and dry, with variable amounts of hemorrhage and edema present.
  • Kidneys may appear swollen, and multiple hemorrhages and edema may be present in the lungs.
  • Nutritional imbalances such as selenium deficiency may predispose animal to developing exterional myopathy.
  • In severe cases, exertional myopathy results in death of the animal.
Meat Edible?
  • Meat from an animal with exertional myopathy is suitable for human consumption, although muscle damage may change the flavor and will decrease the spoilage time of the meat.
  • This condition may occur through normal life-history events, particularly when prey species try to escape predators; however, it is more commonly associated with strenuous use of muscles in the forelimbs and hindlimbs when wild ungulates are captured and handled.
  • This condition is extremely difficult to treat and is best to avoid through prevention.
  • Prevention relies on methods that reduce stress to animals, minimizing pursuit, struggling and handling time, selecting appropriate weather conditions to handle animals, ensuring proper methods of capture and handling, and ensuring animals are released or placed in less stressful conditions as quickly as possible.
Samples for Diagnosis
  • Portions of affected muscles from different areas of the body as well as sections of heart and kidney tissue should be stored in formalin and submitted for microscopic examination.
Further Reading
Return to Manual Home Page Disease List - Body Region Affected Disease List - Causative Agent or Risk Factor Disease Surveillance Form Glossary Contact Information
Return to Manual Home Page Return to Disease List - Body Region Affected Return to Disease List - Causative Agent or Risk Factor Disease Surveillance Form Download Glossary Contact Information