The research confirms long-held theories that CWD can be indirectly spread through environmental sources, in addition to direct interactions between infected and healthy mule deer.
Funded by the National Science Foundation (NSF) and the National Institutes of Health, the study results were published on-line last week in the journal Emerging Infectious Diseases. The authors are Colorado Division of Wildlife (DOW) veterinarians Michael Miller and Lisa Wolfe, Colorado State University (CSU) scientist Thomas Hobbs and University of Wyoming scientist Elizabeth Williams.
"Diseases like CWD are poorly understood and of rising concern," said Sam Scheiner, program director in NSF's division of environmental biology, which funded the research. "This study provides significant new information showing the potential for transfer of the infection through the environment after many months. The knowledge will substantially alter how we manage the disease in wild and domestic animals."
Based on anecdotal observations, "we have long suspected that CWD could be transmitted when healthy deer were exposed to excreta and carcasses of mule deer that had the disease," said Miller. "Our findings show that environmental sources of infection may contribute to CWD epidemics, and illustrate how potentially complex these epidemics may be in natural populations."
Added Williams, "We've had a great deal of circumstantial evidence suggesting that indirect transmission occurs. The experimental findings show that we need to consider several potential exposure routes when attempting to control this disease."