CWD is a disease that destroys the brains of infected deer and elk. It is similar to mad cow disease. Both are known as transmissible spongiform encephalopathies (TSEs).
Although CWD has not been known to infect humans, a new study suggests exposure to the disease should not be taken lightly. In addition to the brain and spinal tissue that are usually regarded as the high-risk areas of an infected animal, the study cautions that exposure to the meat of an infected animal may also be problematic.The study, which appears in the journal Science, that there are still many unknowns about TSEs in general and CWD specifically. The diseases are caused by Ã¢â‚¬Å“rogueÃ¢â‚¬Â proteins known as prions.
These dangerous prions are found in the brain and spinal cord tissue of animals infected with mad cow disease. The muscle meat is not affected. This study, however, found that in the case of CWD, the infected animal carries Ã¢â‚¬Å“prion infectivityÃ¢â‚¬Â in muscle meat during the clinical phase of the disease. Thus, humans handling the meat alone are at risk of exposure.
When infected brain and muscle material from deer was injected into the brains of mice specifically bred to be susceptible to CWE, the mice developed progressive brain dysfunction.
Although the findings were not altogether unexpected, they do raise questions concerning the extent to which these dangerous prions may also be found in the urine and blood of infected animals. No test currently exists to determine the presence of prions in these fluids although there is evidence that they are there.
While it has been the practice of states to warn hunters of handling or consuming the meat from from any deer or elk that show signs of CWE, the possibility that prions may be in the meat of an infected animal before such signs or symptoms are observed raises concern among the study authors.
Notwithstanding the fact that there is a far more substantial Ã¢â‚¬Å“species barrierÃ¢â‚¬Â between CWE and people than there is with respect to mad cow disease, which has already shown the ability to infect humans who consume infected meat, one expert points out that it is Ã¢â‚¬Å“not a zero-risk activity.Ã¢â‚¬Â Thus, even though the probability of infection is very low, hunters should have all meat intended for human consumption tested.