Cooperative Fish and Wildlife Research Units Program: Wisconsin Wildlife
Education, Research and Technical Assistance for Managing Our Natural Resources

Chronic wasting disease (CWD) is a fatal prion disease of cervids which has spread across much of North America. While gold standard CWD diagnostics involve postmortem testing of medial retropharyngeal lymph nodes or obex (brainstem), a key tissue sample for antemortem testing is rectoanal mucosa-associated lymphoid tissue (RAMALT). However, collection of an adequate sample (i.e., enough lymphoid follicles) may be affected by factors such as deer age, repeated sampling, skill of the sampler, and adverse conditions during collection. Here, we document the protocol used to train personnel for RAMALT collection in a large study of free-ranging white-tailed deer (Odocoileus virginianus) in Wisconsin, USA, and determine factors that contributed to the occurrence of inadequate RAMALT samples. Our training protocol included hands-on experience with postmortem tissues, as well as a mentored collection process in the field. RAMALT collection under field conditions was highly successful, with 763 of 806 (94.7%) samples deemed adequate for subsequent testing. While inadequate samples were rare, they were more likely to occur with older deer and when samples were collected at dusk (i.e., limited ambient lighting). We conclude that RAMALT collection can be highly successful under adverse field conditions, including with technicians with limited prior veterinary experience, and we provide details of our training program to facilitate repeatability in other ante-mortem CWD testing efforts.