Undercooked game top trichinosis source
Scientists at the Centers for Disease Control and Prevention say improperly cooked wild game – mostly black bear meat – has become the leading cause of human trichinosis in the United States.
And with more bears and bear hunters in the woods, the risk may grow.
“Increased local bear populations, combined with the popularity of bear hunting in the northeastern United States and Canada, might contribute to increasing cases of Trichinella infection,” according to an editorial note accompanying an article in last week’s edition of the CDC’s Morbidity and Mortality Weekly Report.
Trichinellosis, or trichinosis – long associated with pork – is caused by the consumption of raw or undercooked meat infected with larvae of a round worm called Trichinella.
Victims suffer fever, facial swelling, and weakness, pain and swelling in the muscles. Cardiac and neurological problems or death can follow the most severe infections. Oral medication kills the worms, and corticosteroids will ease inflammation. But fatigue and diarrhea may last for months.
To kill the larvae, the CDC says meat should be heated to a temperature of 170 degrees Fahrenheit or until the muscle fibers are easily separated.
Trichinosis was once a fairly common consequence of eating pork that was not thoroughly cooked. Domestic swine acquired the larvae from eating infected animal products or barnyard rodents. But improvements in swine production have made pork-related infections rare.
These days, the CDC hears of only about a dozen cases of Trichinella infection per year in the United States. But a CDC study in 2003 found that wild game had become the predominant source. Of 72 cases reported to the CDC between 1997 and 2001, 52 could be traced to their meat source. Of those, 31 were linked to wild game, including 29 caused by bear meat.
The disease also has been traced to even more exotic fare – including cougar jerky and the meat of foxes, dogs, wolves, horses, seals and walruses.
In New York state last year, a record 1,850 bears were reported shot by hunters. Cooking instructions were distributed with each bear license, but not everyone got the message.
The CDC said a 54-year-old man was hospitalized in early November, suffering from sweating, fever, weakness, a rapid heartbeat, diarrhea, weight loss and a dry cough. He told doctors he had eaten about 2 pounds of “nearly raw” bear meat during the two weeks before he got sick, the CDC reported. His kill had been custom-butchered and frozen for a week.
Doctors found Trichinella antibodies in his bloodstream. State wildlife pathology officials took 9 pounds of bear meat from the man’s freezer and found as many as 48 larvae per gram of bear meat tested. (A gram equals .035 ounce.)
In October 2003, a man and a woman in Claiborne County, Tenn., were stricken by fever, chills, aches and pains and facial swelling more than a month after they shared a bear meat barbecue. What they didn’t grill they froze, and they continued to eat it during September.
Investigators recovered the remaining frozen meat and counted 350 to 400 Trichinella larvae per gram. All three victims were treated and recovered fully, the CDC said.
Thorough cooking will normally kill the parasites. But the Tennessee couple told investigators they liked their bear steaks medium-rare. Four dinner companions who ordered theirs well-done did not get sick.