New England is entwined in a medical mystery that stretches across species and the country. The clues raise more questions than answers: Three young people, one with links to Maine, have contracted an extremely rare, infectious disease that leads to dementia and death. A strikingly similar disease is killing thousands of deer and elk in the western United States. Elk farms in New England, which cater to an Asian market for aphrodisiacs, are importing animals that officials warn could spread the infection.

And in the background looms the specter of mad cow disease, the British epidemic responsible for the slaughter of hundreds of thousands of cattle, the devastation of the British beef industry, and the death, so far, of more than 40 people. Researchers are struggling to determine if these factors are part of the same trail of evidence or if they are connected only by coincidence and fear.

Either way, there is no denying that federal researchers are worried. How else to explain why a US Department of Agriculture official came to Maine last month to supervise a "harvest" of 299 heads from deer shot during the fall hunting season? "They used a fancy spoon to scoop out a portion near the brain stem for analysis," said Mark Caron, a Maine wildlife biologist.

The reasoning behind the examination of deer brains? One of the young victims of the rare disease who lived in the South had, years before her death, eaten meat from deer her father had shot in Maine.

The Maine samples are part of a nationwide investigation into a family of diseases called transmissible spongiform encephalopathies, or TSE, that do similar damage to the brains of different mammals - deer, elk, sheep, cattle, cats, mink, and humans. But they are subtly different illnesses. And until mad cow disease - the bovine TSE - hit Britain and apparently spread to people who ate infected beef, most scientists believed TSEs did not jump from one species to another.

The possibility that chronic wasting disease - the TSE that affects deer and elk - has made the leap to humans is what had federal researchers concerned enough to survey Maine.

The 28-year-old woman who ate Maine deer died of Creutzfeldt-Jakob disease - the human TSE. There are only five reported Creutzfeldt-Jakob cases per billion worldwide in people 30 years old or under, according to Lawrence Schonberger of the federal Centers for Disease Control.

Yet, since 1996, Creutzfeldt-Jakob disease has been detected in three Americans in that age group; two are dead and one is dying. All three, it turns out, had hunted extensively or eaten venison.

"It may be a coincidence," said Dr. Pierluigi Gambetti, professor of pathology and director of the National Prion Disease Pathology Surveillance Center at Case Western University in Cleveland, where the Centers for Disease Control sends its human brain samples. "It would be imprudent to say there is a danger of an epidemic. But, yes, it's something that has to be studied."

Said Thomas Pringle, a biochemist who runs a Web site on TSEs: "What has CDC worried is that the original tip-off in Britain that something was wrong was the upsurge in cases of Creutzfeldt-Jakob disease in young people."

The CDC medical epidemiologist, Ermias Belay, citing a Red Cross survey, emphasized that since 40 percent of Americans have eaten wild venison at least once, the three cases could be explained by chance alone. "If there had been one more," he said, "it might tip the balance."

But, countered Michael Hansen, a research associate at Consumer's Union, "Given how rare the disease is in young people and how difficult it is to make a diagnosis, the possibility that some cases go undetected cannot be ruled out."

That is what nearly happened last year in Utah to Tracie McEwan. The young wife and mother of two watched desperately as, over a few months, her 28-year-old husband, Doug, lost motor control and memory, became disoriented, and suffered dramatic moods swings.

"After doctors performed hundreds of tests," Tracie recalled, "I saw a television show about mad cow disease." She demanded the doctors test for Creutzfeldt-Jakob disease. A brain biopsy confirmed her fears.

"We have decided to get pretty aggressive, primarily because of the situation in Britain," said the CDC's Schonberger. He emphasized, however, that "none of the three cases has been linked to chronic wasting disease in deer and elk.

While the threat to humans remains theoretical, the danger of the disease within deer and elk populations is real and growing. "It's been spreading slowly since it was first found in the wild in 1981," said Beth Williams, a professor of veterinary services with the University of Wyoming. Chronic wasting disease is now a major problem in Colorado and Wyoming, infecting 4 to 8 percent of the 62,000 deer there and 1 percent of elk, she said.

In states other than Wyoming and Colorado, tests on 4,500 seemingly healthy wild animals have found no evidence of disease, but that sampling does not fully allay scientists' concerns. TSEs are caused by prions, a puzzling protein-like substance that is extremely difficult to detect or kill. Prions can remain infectious on correctly sterilized surgical instruments and have been transmitted through corneal transplants, growth hormones, and meat that has been thoroughly cooked.

They are also apparently passed among deer and elk by routine kinds of contact. Outbreaks of chronic wasting disease have spread among farmed elk not only in Colorado and Wyoming, but in other parts of the West, forcing the destruction of herds and the quarantining of farms. Montana saw its first confirmed case last month.

So far New England appears to be free of the disease, but the chance of infection rises with the number of western elk shipped east to supply the region's growing elk farming industry. The animals are prized for the velvet on their antlers, believed in some parts of Asia to be aphrodisiacs.

"Elk farming is the recipe for introducing CWD into areas where it has not existed before," said Dr. Victor Nettles, director of the Southeastern Cooperative Wildlife Disease Study, referring to chronic wasting disease.

"We are at the extremely initial stage of awareness and monitoring," warned Robert Deblinger, assistant director of the Massachusetts Wildlife Division. "But states need to be aggressive. It's only going to get worse, so it's important to be vigilant. That is the only way you keep the diseases out."

Of immediate concern to New England's wildlife managers is the health of native deer, which support the region's multibillion-dollar hunting industry. Since there is a two- to five-year incubation period and no reliable test for live animals, apparently healthy elk can harbor and spread the disease.

The elk-trading network is extensive and loosely regulated. Paperwork that accompanies each elk to Vermont, for example, tells only where the animal was bought, not where it was a year or even a month before. And if the herd it passed through later has an outbreak of chronic wasting disease, there are no procedures to trace exposed elk or issue warnings.

Vermont, Maine, and New Hampshire have not formally notified elk farmers to be on the lookout for neurological symptoms, nor do they require reporting of suspicious symptoms. In Vermont, when one of the state's 250 captive elk dies, the owner may comply with a voluntary program for testing.
"From the standpoint of protecting wildlife," said Steve Weber, chief of New Hampshire's Wildlife Division, "a ban on elk farming is the prudent thing to do, but when balanced against existing industry, there are trade-offs you make." New Hampshire has a handful of elk farms and a few hundred elk, Weber estimated.

So far, Massachusetts is the only New England state to ban elk farming. "Anytime you want to fence in a wild animal it's going to get out," warned Robert Deblinger, assistant director of the Massachusetts Wildlife Division. "We worry about interbreeding and genetic pollution as well as the introduction of chronic wasting disease."

That infected western elk can transmit TSE to native New England deer is established science. The more troubling - and as yet unsolved - mystery is whether, like its bovine counterpart, chronic wasting disease can, or has, jumped species to infect humans.

GRAPHIC: PHOTO, Elk farms in New England could bring a rare, infectious disease to the region. The animals are imported from western states. / AP PHOTO. LOAD-DATE: December 16, 1999