Hanna Chriss

Chronic Wasting Disease (CWD) is a 100% fatal prion disease affecting cervids, including white-tailed deer, moose, elk, and caribou. CWD was first identified in Colorado in the 1960s and has since spread across the United States and Canada. Given the spread of CWD in wild and farmed deer, there is growing urgency to identify new surveillance mechanisms. CWD prions are resistant to degradation and can remain in the environment for at least 15 years. Given their persistence in the environment, a number of environmentally-based surveillance options can be pursued. In April of 2021, a CWD-positive white-tailed deer farm was identified in Beltrami County, Minnesota. The farm was depopulated and ~22% of the herd (n=54) was CWD positive. Our team subsequently visit the farm and collected environmental samples for downstream testing. We observed multiple fly traps used to control pest insects that were associated with the deer herd. In light of this observation, we hypothesized that blood and carrion-feeding insects might serve as a xenodiagnostic surveillance tool for the detection of CWD prions. To test this hypothesis, we used a cutting-edge seeded-amplification prion detection assay, known as RT-QuIC, to examine trapped insects associated with the CWD-positive deer herd for the presence of CWD prions. Additionally, we used single-molecule nanopore sequencing to molecularly barcode the insects for species-level identification. Here we present RT-QuIC and nanopore sequencing data that 1) indicate CWD prions can be identified in herd-associated insects and 2) reveal the species of insects that were associated with. In addition, we used molecule barcoding techniques to identify the fly species involved. We conclude that flying insects represent a novel surveillance tool for farm cervids and potentially wild cervids. To our knowledge, this research presents the first case of a xenodiagonsitic approach for prion disease surveillance.