Family infected with parasitic worms from undercooked black bear meat, CDC reports

Two American black bears (Ursus americanus) play fighting / playfighting / playing and splashing in water of pond. (Photo by: Philippe Clement/Arterra/Universal Images Group via Getty Images)

Several family members, including some from Minnesota, were infected with parasitic worm larvae after sharing a meal with black bear meat, a recent report from the Center for Disease Control and Prevention (CDC) says.

According to the CDC, the Minnesota Department of Health (MDH) was notified in July 2022 after a 29-year-old man was hospitalized with a fever, severe muscle pain, eye swelling, and other abnormalities. The man was hospitalized twice over 17 days with the symptoms. 

The second time he was hospitalized, doctors learned the man had eaten a meal during a family gathering in South Dakota that included kabobs made from black bear meat, six days before his symptoms set it in. The meat had been harvested by one of the other family members in northern Saskatchewan, Canada, a few months earlier, in May 2022, the CDC said. 

The black bear meat had been frozen for 45 days, when it was thawed out and grilled with vegetables. The meat was unintentionally served rare, initially. The CDC says, reportedly, the meat was dark in color, and making it difficult for the family to see how done the meat was. 

The family then noticed the meat was undercooked while eating it, and it was recooked and served again. 

Eventually, doctors diagnosed the man with trichinellosis, an infection caused by the larvae of a parasitic roundworm, according to the CDC. People get the infection from eating meat from animals infected with the parasite, usually from meat-eating animals, like black bears. 

Trichinellosis is rare in the U.S., with about 15 confirmed cases a year. 

Once a human is infected, the larvae can travel through the body through the bloodstream, then bury themselves in muscle tissue, according to the Mayo Clinic. In serious cases, the brain, heart and lungs can be affected, the Minnesota Department of Health says. 

Six of the eight family members who attended the meal, including four who ate the bear meat and two who only ate the vegetables that were served with the meat, had symptoms of the infection, the CDC said. The family members with trichinellosis ranged in age from 12 to 62. Four of the family members were from Minnesota, while one was from Arizona and one from South Dakota. 

Three of the six family members who were symptomatic were hospitalized, and were treated with albendazole. According to the Mayo Clinic, albendazole keeps the worms from absorbing sugar, so it loses energy and dies. 

All six who were infected have recovered, the CDC said. 

Freezing can kill the worms, called trichinella, but some species are freeze-resistant, especially ones in Arctic and sub-Arctic areas. The CDC recommends cooking wild game meat to an internal temperature of around 165 degrees, and should be checked with a meat thermometer. Also, raw meat should be separated from other foods when cooking, to help prevent cross-contamination.