Chapter 6, Problem 4CHI

Chronic wasting disease (CWD) is a neurodegenerative disease of cervid animals (e.g., deer, elk, moose) caused by prions. Unlike other prion diseases, CWD is readily transmitted from one animal to another in a herd. How this occurs in not understood. However, evidence suggests the mode of transmission is by animal excreta: saliva, urine, and feces. In this mechanism, a healthy animal would be exposed to the prion present in excreta from a diseased animal. Since many cervids congregate, the prion would easily spread from one animal to another. One problem facing scientists studying CWD is measuring the amount of infectious prions in excreta and determining their source (i.e., whether they are produced solely in nervous system tissue or in organs of excretion). Why is CWD of concern to fish and wildlife biologists and game managers in states where CWD is prevalent (e.g., Colorado, Wyoming, Wisconsin)? Why would the presence of CWD prions in tissues other than those of the central nervous system be important to know? (Hint: Learn about the variant Creutzfeldt-Jakob epidemic that occurred in the 1990s.)

Read the original article: Haley, N. J., et al. 2011. Detection of chronic wasting disease prions in salivary, urinary, and intestinal tissues of deer: potential mechanisms of prion shedding and transmission. J. Virol. 85:6309.