A family reunion’s bear feast turned into a medical disaster, thanks to some parasitic worms. In a recent paper, scientists with the Centers for Disease Control and Prevention detail how the family caught trichinellosis from contaminated bear meat that wasn’t cooked thoroughly enough. Several family members became so sick that they had to be hospitalized, though thankfully everyone recovered.
The strange outbreak was described over the weekend in the CDC’s Morbidity and Mortality Weekly Report.
Officials at the Minnesota Department of Health first became aware of the outbreak in July 2022, after a 29-year-old man had been hospitalized twice over the span of 17 days with symptoms of fever, severe muscle aches, and swelling around his eyes. During his second visit, doctors learned that he had attended a family reunion in South Dakota a week before his symptoms began—a reunion where people were served kebabs made of black bear meat collected from a hunt earlier that May in northern Saskatchewan (black bear hunting is legal throughout Canada). Eventually, doctors confirmed that the man had developed an infection from a species of Trichinella, parasitic roundworms that can infest many different animals, humans and bears included.
Health officials in Arizona, Minnesota, and South Dakota (the states where the family members resided) then reached out to the other reunion guests. They also got ahold of the remaining meat, which tested positive for Trichinella worms. The disease detectives, along with the CDC, determined that six out of the eight interviewed family members caught trichinellosis from the reunion—with two having been infected by only eating vegetables that had been cooked or served next to the contaminated meat.
Trichinellosis is typically associated with undercooked pork, but improved food safety practices have made these cases a very rare occurrence in North America and other developed parts of the world. Nowadays, most outbreaks here are instead caused by eating contaminated wild game meat, with bears being a common culprit. And it seems that the particular choice of bear meat made it easier for this outbreak to occur in the first place.
The officials found that the meat was accidentally served quite rare at first, for instance, because the naturally dark color of the meat made it hard to distinguish how well cooked it was from a simple glance (some of the meat was reheated after guests noticed that it was undercooked). The specific species of worm found in the bear meat, Trichinella nativa, is also resistant to freezing, unlike the worms more commonly linked to pork, meaning that the family’s freezing of the meat for 45 days prior to serving it did next to nothing to stop contamination.
Three of the six family members were ultimately hospitalized as a result of their infection, but luckily all six recovered from their ordeal. And any kind of trichinellosis remains rare in the U.S., with only 35 cases documented between 2016 to 2022, according to the CDC. But this outbreak should provide an important lesson to wild game hunters and their families, officials say.
“Persons who consume game meat, especially that harvested in northern latitudes, should be informed that adequate cooking is the only reliable way to kill Trichinella parasites,” the report authors wrote. They added that this meat should be cooked to an internal temperature of over 165 degrees Fahrenheit and confirmed via meat thermometer, given that “the color of meat is not a good indicator of cooking adequacy.”