Three in hospital after eating undercooked bear meat

They had met for a bit of a family reunion.

Nothing says ‘happy family reunion’ like a big slab of bear meat.

Unfortunately for one group, the bear in question was riddled with a rare worm that in humans causes severe illness, and can wriggle its way around the body.

It all started when the family gathered in South Dakota for a get-together back in July 2022. On one particular evening, they sat down to a special meal of kebabs made with black bear meat. The bear had been ‘harvested’ by one family member from northern Saskatchewan, Canada, and left in the freezer for 45 days.

It was then grilled alongside an array of vegetables – but with no meat thermometer to hand, the chef eyeballed whether it was done or not. After some of the family noted it was still rare, the meat was recooked and served again.

Within days, several members of the family had fallen ill, including one, a 29-year-old man from Minnesota, who was twice hospitalised. His symptoms included a fever, swelling around his eyes and severe muscle pain, while tests showed a high level of white blood cells, indicating he was battling an infection of some sort.

It was during his second stay in hospital that doctors heard about the bear meat feast, and put two and two together.

The patient, and five other relatives, had all been infected by Trichinella nativa larvae, leading to trichinellosis.

The roundworms are typically found in the muscle fibres of cold-adapted species, such as bears, moose, boars and walruses. This means that while freezing often kills other types of Trichinella found around the world, in this case, they survived.

And because the meat was served rare, and not cooked to an adequate temperature of at least 74C, they also weren’t killed by heat exposure.

This led to three of the family being hospitalised, including a 12–year-old. Six of those at the meal were infected, although two who only ate the vegetables cooked alongside the bear, showing cross-contamination also occurred.

Once eaten, the worm larvae bury their way into the small intestine, where they grow into fully fledged worms. These worms then mate and produce more worms – it is this second generation that then begins to migrate around the body. 

In the case of Trichinella nativa, they typically find their way into muscles, but other species can make their way right up to the brain.

It is when the worms begin spreading around the body that the worst symptoms appear, including inflammation of the heart.

Luckily for this family, everyone recovered. The patients who were hospitalised were treated with an anti-parasitic drug, albendazole, while the other three did not require any medication.

Cases of trichinellosis are rare in the US, with just seven outbreaks between 2016 and 2022 – but most were linked to eating bear meat.

The Centers for Disease Control, which reported the most recent case in its Morbidity and Mortality Weekly Report, warned that adequately cooking game meat is the only reliable way to kill the parasites before eating.

For this family, it’s a lesson well learned – but they still threw out the rest of the bear.