Sample of bear muscle tissue, digested. Image photographed at 100x magnification.

The first symptoms of trichinellosis are gastrointestinal, usually occurring 1–2 days after a person consumes raw or undercooked meat from a Trichinella-infected animal. These symptoms include the following:

  • Nausea
  • Diarrhea
  • Vomiting
  • Abdominal pain

The following classic symptoms of trichinellosis often occur within 2 weeks after eating contaminated meat, and can last up to 8 weeks:

  • Muscle pain
  • Fever
  • Swelling of the face, particularly the eyes
  • Weakness or fatigue
  • Headache
  • Chills
  • Itchy skin or rash
  • Cough
  • Diarrhea
  • Constipation

Symptoms may range from very mild to severe and relate to the number of infectious worms consumed in the meat. Many mild cases of trichinellosis are never specifically diagnosed because they are assumed to be the flu or other common illnesses. Furthermore, many people with trichinellosis do not experience any symptoms at all.

If the infection is heavy, persons may have trouble coordinating movements and have heart and breathing problems. Although rare, death can occur in severe cases. For mild to moderate infections, most symptoms go away within a few months.

Page last reviewed: November 18, 2019