Species barrier may protect humans eating deer, elk from chronic wasting disease

Washington, July 31 (ANI): A study on monkeys suggests that people who consume deer and elk with chronic wasting disease (CWD) may be protected from infection by an inability of the infectious agent to spread to people.

Researchers at Rocky Mountain Laboratories (RML) in Hamilton, Mont, carried out this study as part of an ongoing multi-year study.

During the study, the researchers exposed 14 cynomolgus macaques orally or intracerebrally to CWD.

They found that the monkeys remained healthy and symptom free after more than six years of observation, though the direct relevance to people is not definitive and remains under study.

The researchers say that the reason why they used cynomolgus macaques as research models was that they are very close genetically to humans, and are susceptible to several forms of human brain-damaging disease.

Writing in the online edition of the journal Emerging Infectious Diseases, they have revealed that they wanted determine whether exposure to CWD could induce disease in the macaques.

CWD is a type of brain-damaging disease known as a transmissible spongiform encephalopathy (TSE) or prion disease. It primarily affects deer, elk, and moose.

Other TSE diseases include mad cow disease, or bovine spongiform encephalopathy (BSE) in cattle, scrapie in sheep, and sporadic Creutzfeldt-Jakob disease (CJD) in humans.

Although humans are not susceptible to sheep scrapie, BSE seems to have infected about 200 people, primarily in Europe in the 1990s.

The researchers say that all these findings provide the rationale for their CWD-macaque study, which began in 2003.

"We plan to continue this study for at least several more years because, although the risk to macaques so far appears to be low, we know that these diseases can take more than 10 years to develop," says Dr. Bruce Chesebro, chief of the Laboratory of Persistent Viral Diseases at Rocky Mountain Laboratories (RML) in Hamilton, Mont.

The RML study also included identical testing in squirrel monkeys, which are genetically less similar to humans than macaques.

The results in squirrel monkeys confirmed that disease progression in that species appears consistent with disease progression in deer and elk, where severe weight loss is nearly always present.

"The fact that the squirrel monkeys, like the deer and elk, suffered severe weight loss suggests that chronic wasting disease might affect a common region of the brain in different species," says Dr. Chesebro. (ANI)