Dogs can Generalize from Cotton Training Aids to Fecal Matter in Chronic Wasting Disease Detection

Chronic wasting disease (CWD) is a prion-associated transmissible spongiform encephalopathy (TSE) that causes fatal neurodegeneration in cervids. One promising method for CWD surveillance is the use of detection dogs trained to differentiate between fecal matter from CWD-positive (infected) and CWD-negative (noninfected) deer. However, using actual fecal matter during the training process confers a biohazard risk. Chronic wasting disease detection dogs trained on fecal matter can differentiate between CWD-positive and CWD-negative training aids, including cotton aids, which are inexpensive and simple to use. However, as most dogs in an applied setting would instead be trained on aids and tasked with finding actual fecal matter in the field, this study examined 1) the extent to which dogs initially trained on CWD-incubated cotton can discriminate between fecal samples from CWD-positive and CWD-negative deer; and 2) the impact of substrate form (cotton ball or cotton roll) on the dogs' detection accuracy. Results show that dogs (n=5) maintained an accuracy of >80% during training while discriminating between cotton ball training aids that had been incubated (noncontact) with deer fecal samples confirmed as either CWD-positive or CWD-negative. When tested with cotton ball training aids incubated with novel samples, dogs (n=4) showed 73% sensitivity and 77% specificity. When presented with deer fecal samples, dogs showed a sensitivity of 50% and a specificity of 90%. The type of cotton (ball or roll) did not significantly influence performance. In sum, cotton aids can be used to train dogs to detect the CWD odor profile effectively. However, an initial reduction in sensitivity suggests that integrating exposure to target fecal matter may enhance detection performance.