Kentucky Doctors Warn Against a Regional Dish: Squirrels' Brains
By SANDRA BLAKESLEE
Published: August 29, 1997
Doctors in Kentucky have issued a warning that people should not eat squirrel brains, a regional delicacy, because squirrels may carry a variant of mad cow disease that can be transmitted to humans and is fatal.
Although no squirrels have been tested for mad squirrel disease, there is reason to believe that they could be infected, said Dr. Joseph Berger, chairman of the neurology department at the University of Kentucky in Lexington. Elk, deer, mink, rodents and other wild animals are known to develop variants of mad cow disease that collectively are called transmissible spongiform encephalopathies.
In the last four years, 11 cases of a human form of transmissible spongiform encephalopathy, called Creutzfeldt-Jakob disease, have been diagnosed in rural western Kentucky, said Dr. Erick Weisman, clinical director of the Neurobehavioral Institute in Hartford, Ky., where the patients were treated.
''All of them were squirrel-brain eaters,'' Dr. Weisman said. Of the 11 patients, at least 6 have died.
Within the small population of western Kentucky, the natural incidence of this disease should be one person getting it every 10 years or so, Dr. Weisman said. The appearance of this rare brain disease in so many people in just four years has taken scientists by surprise.
While the patients could have contracted the disease from eating beef and not squirrels, there has not been a single confirmed case of mad cow disease in the United States, Dr. Weisman said. Since every one of the 11 people with the disease ate squirrel brains, it seems prudent for people to avoid this practice until more is known, he said.
The warning, describing the first five cases of Creutzfeldt-Jakob disease, will appear in tomorrow's issue of The Lancet, a British medical publication.
The disease in humans, squirrels and cows produces holes in brain tissue. Human victims become demented, stagger and typically die in one or two years. The people who died from Creutzfeldt-Jakob disease in Kentucky were 56 to 78, lived in different towns and were not related, Dr. Weisman said.
The cause of transmissible spongiform encephalopathies is hotly debated. Many scientists believe that the infectious agent is a renegade protein, called a prion, which can infect cells and make copies of itself. Others argue that a more conventional infectious particle causes these diseases but that it has not yet been identified. In either case, the disease can be transmitted from one animal to another by the eating of infected brain tissue.
Such diseases were considered exotic and rare until 10 years ago, when an outbreak occurred among British cattle. Tens of thousands of animals contracted a bovine variant called mad cow disease, and their meat along with bits of brain tissue was sold as hamburger. Thus far 15 people in Britain have died of a transmissible spongiform encephalopathy that they seemed to have contracted from eating infected meat.
Most people with Creutzfeldt-Jakob disease are elderly, but the British victims were all young, which alarmed public health officials. The outbreak in western Kentucky has occurred in older people, Dr. Weisman said, ''which makes me think there may have been an epidemic 30 years ago in the squirrel population.'' Transmissible spongiform encephalopathies have a long latency period, he said, which means many people in the South may be at risk and not know it.
Squirrels are a popular food in rural Kentucky, where people eat either the meat or the brains but generally not both, Dr. Weisman said. Families tend to prefer one or the other depending on tradition. Those who eat only squirrel meat chop up the carcass and prepare it with vegetables in a stew called burgoo. Squirrels recently killed on the road are often thrown into the pot.
Families that eat brains follow only certain rituals. ''Someone comes by the house with just the head of a squirrel,'' Dr. Weisman said, ''and gives it to the matriarch of the family. She shaves the fur off the top of the head and fries the head whole. The skull is cracked open at the dinner table and the brains are sucked out.'' It is a gift-giving ritual. The second most popular way to prepare squirrel brains is to scramble them in white gravy, he said, or to scramble them with eggs. In each case, the walnut-sized skull is cracked open and the brains are scooped out for cooking.
These practices are not a matter of poverty, Dr. Berger said. People of all income levels eat squirrel brains in rural Kentucky and in other parts of the South. Dr. Frank Bastian, a neuropathologist at the University of South Alabama in Mobile, said he knew of similar cases of Creutzfeldt-Jakob disease in Alabama, Mississippi and West Virginia.
Squirrel hunting season began last week, and it lasts through early December, Dr. Berger said. He and Dr. Weisman are asking hunters to send in squirrel brains for testing, including those taken from dead animals found on the roadside. A mad squirrel would be more likely to stagger into the road and be struck by vehicles, Dr. Berger said.