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Trichinellosis

Trichinellosis is a reportable disease in Oklahoma.  Trichinellosis, also called trichinosis, is an infection caused by the roundworm Trichinella. In the first half of the 20th century, several hundred cases occurred annually in the United States. Following eradication programs in the domestic pork industry, trichinellosis became rare in the U.S., with most cases associated with eating wild game. Between 1997-2004, fewer than 11 cases a year on average have been reported in the U.S. Trichinellosis is rare in Oklahoma as well; only two cases have been reported to the Oklahoma State Department of Health since 1978.

People become infected with Trichinella worms by eating raw or undercooked meats from infected animals. In the U.S., eating raw or undercooked game, such as wild boar, bear, and cougar, is most often the cause of infection in people.  However, travelers to foreign countries with inadequate trichinellosis control programs should avoid eating undercooked pork and pork products, such as sausage. Outbreaks have occurred in Europe from infected horse meat. Persons with trichinellosis do not spread the infection to others.

Trichinella infections can range from a mild flu-like illness to a severe, potentially fatal disease. The sudden appearance of muscle soreness and pain along with swelling of the upper eyelids are characteristic early signs of trichinellosis. Headache, fever, sensitivity to light, thirst, sweating, chills, cough, and itchy skin are other possible symptoms. Persons with severe disease may experience difficulty coordinating movements, and may develop heart and breathing problems. Most symptoms are mild or moderate in severity and will resolve within a few months. However, diarrhea, weakness, and fatigue may last longer.

Stomach problems may begin within a few days, but the characteristic symptoms begin five to 45 days after eating infected meat.  A blood test or muscle biopsy, performed by a physician, is used to diagnose trichinellosis.

Trichinellosis cannot be spread to others. Infection can only occur by eating raw or undercooked meat containing Trichinella worms. The worms are present in infected animals for months, and their meat can cause infection unless cooked, frozen, or irradiated to kill larvae.

How to prevent Trichinellosis:

  • Cook potentially infected meat products until no longer pink inside or to an internal temperature of 160° F.
  • Freeze pork less than 6 inches thick for 30 days at 5° F to kill worms.
  • Cook wild game thoroughly. Unlike species found in pork, some Trichinella in wild animals can survive freezing.
  • Do not allow hogs to eat uncooked carcasses of other animals, including rats, which may be infected with trichinellosis.
  • Clean meat grinders thoroughly between each use and avoid mixing ground meats from different animals.

Trichinellosis Fact Sheets and Information:

Trichinellosis Fact Sheet (38k.pdf)
  Hoja Infomativa Triquinelosis (125k.pdf)

External Trichinellosis Resources:

Trichinellosis (CDC)

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