Once again Alaskans are being warned about the danger of undercooked meat from animals that carry the trichinellosis roundworm.
Three years ago, the problem was with a group of out-of-state hunters who enjoyed a meal of bear cooked over an Alaska campfire. They went back to their homes in the Lower 48 only to get sick.
Now the problem is with the meat of walrus.
The Centers for Disease Control this week reported two outbreaks of trichinosis in Northwest Alaska, one last fall and earlier this year. They were enough to spark CNN to headline that people should “Use caution eating walrus meat in Alaska.”
“Anyone looking to enjoy some walrus meat should be sure it’s thoroughly cooked,” the story began.
Few people enjoy walrus meat. It is not readily available in Alaska. The animals live in the remote Bering Sea. And legally they can only be hunted and killed by Alaska Natives, who are prohibited from selling the meat.
So you can’t get walrus in stores or restaurants in the 49th state. The legal restrictions pretty much limit the supply of walrus meat to 30,000 to 35,000 people living along the Bering Sea coast and whatever friends and relatives they might share the meat with elsewhere in Alaska.
Beware the bear
For most Alaskans, or people visiting Alaska, bear meat poses a significantly greater danger than walrus. Bear meat is regularly eaten by residents of the 49th state and visiting hunters.
The 2014 incident was a reminder the trichinellosis parasite is widespread and the meat of carriers needs to be cooked until well done, as Dr. Louisa Castrodale, an epidemiologist and veterinarian with the Alaska Department of Health, has warned.
The sickened non-resident hunters, she told Riley Woodford, a writer for the state-run Alaska Fish & Wildlife News, “came up to hunt from four different states, and after they got home they started emailing back and forth, ‘Are you sick? I’m sick.’ They figured it out,.
“One person from Washington had some meat and had the Washington Health Department test it, and it was positive.”
Trichinosis or trichinellosis (it’s called both) is caused by a tiny nematode. The species spiralis is fairly common to domestic pigs. Thus people are regularly warned that pork must be well cooked even though thorough freezing will kill spiralis.
Unfortunately for Alaskans, its cousin – the species T. nativa – is a tougher parasite. Freezing won’t kill it, and it can be found in the meat of Alaska bears – black, grizzly (brown) and polar, wolves, foxes, coyotes, sled dogs, lynx, walrus, various kinds of seals, and Beluga whales.
Of these animals, black bears and the various marine mammals are the only ones widely eaten in Alaska, and the latter almost solely by Native residents of the coast or their friends or families elsewhere.
The U.S. Geological Survey in a 2013 report titled simply “Trichinosis” warned that “Alaska has the highest rate of trichinosis” in the U.S. The reason why is simple:
More than 10 percent of the black bears tested in the state have found to be carriers, and about the same percentage of walrus. A stunning 55 percent of polar bears were found to be carriers, as well.
“It has been suggested that three Swedish explorers searching for the North Pole by balloon in 1897 died as a result of trichinosis,” the USGS report says. “After crashing onto the ice, the explorers were forced to hunt and eat polar bears, which they ate partially
cooked or raw. Their remains and diaries detailing their ordeal were found 30 years later. A polar bear carcass with Trichinella larvae was also found in their camp.”
See a doctor
Trichinosis is usually not deadly, but the USGS report noted that “in 1863, 158
people in Germany were infected with Trichinella by eating infected pork, and 28 of those people died.”
Shortly after that, German authorities started scrutinizing what pigs were fed to make pork safer, and food-safety practices in the developed world have only become better over the years. Trichinosis from pork is now rare.
But the USGS reports “trichinosis has been specifically named as a direct threat
to human health in communities that rely on wildlife as a source of food.” A lot of rural Alaska communities fall in this category.
The latest Alaska cases, according to the CDC, originated with Norton Sound walrus meat shared in the Nome area last summer and again this spring. The first case involved five people who ate raw or pan-fried walrus, according to the CDC. All recovered fully.
The second case involved another five people who ate previously frozen walrus meat kept in a chest freezer.
“The meat was prepared by patient H, 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 CDC reported. “Interviewed persons reported that many community members prefer the taste and texture of undercooked or raw walrus meat to that of fully cooked meat.”
The CDC is discouraging that practice. All five of the patients in the second case were treated and fully recovered.
The CDC warns that signs of infection generally start with diarrhea, abdominal pain, vomiting, fatigue and nausea a day or two after eating contaminated meat. This is followed by facial swelling, fatigue, fever and chills, headache, muscle soreness, difficulty coordinating movements, neurological complications and cardiopulmonary impairment one to two weeks after the meal.
Before the latest cases, the CDC reported, Alaska has gone 23 years without an outbreak related to walrus, but no one knows why. The possibilities are many: lower parasites load in walruses, fewer people eating walrus meat, different preparations or simply people getting sick and recovering without seeing a doctor who diagnosed trichinosis.
The latest outbreak is a warning that the old disease is still out there, the CDC said, and “these outbreaks…highlight the importance of culturally sensitive public health messaging. In areas where wild game species are harvested for subsistence, traditional methods of collecting, handling, preparing, storing, and consuming meat often have great cultural significance; however, some of these methods can be inconsistent with public health best practices.”
Patients who ingest large number of larvae may suffer the effects of the infection
for up to 10 years after recovery, the USGS warns. Up to 90 percent of those seriously affected suffered long-term muscle aches, 59 to 63 percent have continuing vision problems, and 35 to 52 percent come down with nervous system disorders.
“Some patients may suffer protracted recoveries with depression and fatigue due to psychological effects of infection,” the USGS report added.
Science sometimes teaches people about dangers that force cultural modifications. The Japanese, for instance, are now very careful about eating raw salmon because of the dangers of parasites in those fish. Salmon to be eaten raw in Japan are now frozen to kill parasites or sliced thin and placed on a light table so parasites can be detected.
Unfortunately for Alaskans, the only option with walrus, bear and other meat appears to be thorough cooking. Drying, cooking, smoking and slow-cooking in a crock pot won’t work, according to Alaska Department of Fish and Game veterinarian Kimberlee Beckmen.
To be safe, the internal temperature of the meat must reach 160 degrees. Get a cooking thermometer.
CORRECTION: This story was edited on July 7, 2017 to fix an error in the number of people who were infected by eating walrus in the latest case.
Walrus isn’t on my menu.
Thank you for putting in the cooking temp at the end. That’s the kind of detail that completes the story.
My understanding re:trichinosis in pork is that it is very rare. See USDA Aphis link.
Note to self….don’t eat my sled dogs….they may have trich……oh yeh, they are all on he bed….hahahahahaha
Craig, thanks for a really nice companion piece to our report. It adds some very valuable details that provide context and expand the breadth of our coverage. Great to see someone taking the time to study and understand the issue and explain so clearly to a lay audience. Best, Yuri
Craig, thanks for a very nice companion piece to our report. It provides great context and additional, more detailed information that sheds valuable light on the larger issues highlighted in our investigation summary. One minor correction: both outbreaks involved 5 cases, and all 10 patients fully recovered. Best, Yuri