Illness outbreaks linked to undercooked walrus
Two recent outbreaks of a parasitic disease in western Alaska have been linked to the consumption of raw or undercooked walrus meat.
The outbreaks happened between July 2016 and May 2017 in two communities in the Norton Sound region. They are the first times since the early 1990s that multiple people have become sick in linked cases from eating walrus in Alaska, according to the Centers for Disease Control which issued a report earlier this month.
Trichinellosis is a parasitic disease caused by eating raw or undercooked meat that's been infected by a type of roundworm. Pork is the most common carrier, though it's also sometimes found in game meat like bear, seal, and walrus.
Within a day or two of eating the contaminated meat, people may get diarrhea, abdominal pain, nausea, vomiting, and fatigue, the Alaska Division of Public Health's epidemiology section noted in a warning. Within one to two weeks, people may develop facial swelling, fever and chills, headaches, muscle and joint pain, itchy skin, and rashes, which may last up to two months.
In the first case of the earlier outbreak, which was reported on Aug. 31, a young woman came into her local village health clinic for swelling of her legs, difficulty walking, a rash, weakness, and fever, the CDC said.
Her brother and father, who went to the clinic with her, were also checked for illness. All three family members were found to have a higher than usual white blood cell count, called eosinophilia, which is a common symptom of this type of infection.
According to the CDC report, the family said they'd eaten raw or pan-fried "to medium doneness" walrus meat in mid-July.
The aunt and uncle of the girl were also found to have the disease about a month later.
"Leftover walrus meat was not available to test for Trichinella larvae, and investigators could not determine when the walrus had been harvested, how widely associated meat had been shared, or whether all five patients had consumed meat from the same animal," the report's authors wrote.
The first case of the second outbreak was reported on May 12, when a man ended up at the Norton Sound Regional Hospital with "severe muscle and joint pain."
Staff at the Nome Public Health Center and the Alaska Department of Public Health conducted interviews with people in the community and found four other people they thought might be sick.
"These patients were from two neighboring households that included members who hunted walrus together and shared the harvested meat," the report stated.
The walrus was harvested and butchered by two of the patients over the previous one to three months.
"The meat had been stored frozen in unlabeled bags in their respective household chest freezers. The meat was prepared by [one of the women], who reported that she boiled it for approximately one hour, after which the exterior was fully cooked, but the interior remained undercooked or raw, which was the desired result," the report noted. "[I]nterviewed persons reported that many community members prefer the taste and texture of undercooked or raw walrus meat to that of fully cooked meat."
All of the patients from both outbreaks recovered fully following treatment.
Since 1975, 241 trichinellosis cases have been reported in Alaska, with the majority of them caused by eating walrus meat. Before last year, the number of cases seen annually had dropped off sharply.
"Before the outbreaks described here, only one walrus-associated trichinellosis case had been reported in Alaska in the preceding 23 years," the CDC report noted. "Reasons for this decline in incidence are unknown and might involve changes in parasite burden in walruses; the timing or location of walrus hunting; methods used to store, collect, handle, or prepare walrus meat for consumption; reporting practices among ill persons; and clinical testing methods or practices. These outbreaks underscore the importance of inquiring about consumption of commercially prepared and personally harvested meats, and about methods of meat preparation, when evaluating suspected trichinellosis cases, especially in areas where consumption of wild game in association with recreational or subsistence hunting is common."
To avoid getting sick, the Alaska public health officials recommend cooking meat thoroughly before eating it. This particular parasite cannot be "reliably killed" by drying, fermenting, or smoking the meat, which are traditional preparation methods.
The safest way of preparing walrus — which will kill the parasite — is to heat it to 160 degrees Fahrenheit or hotter, making sure to check it with a food thermometer to ensure the internal temperature is high enough, as meat can be fully cooked on the outside but not on the inside. People are also advised to wash their hands after handling raw meat and clean meat grinders completely after they've been used on raw meat.
More information on safe meat preparation and health and wellness can be found by contacting your local public health department or village clinic.
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