Chronic wasting disease (CWD) is a fatal disease that affects species in the deer family including New York State’s most popular game animal, white-tailed deer. CWD is caused by a misfolded version of a normal cellular protein; the misfolded version is called a prion. Misfolding makes CWD prions transmissible and infectious; when prions contact normal proteins in an animal, they cause the normal proteins to misfold and become prions. Groups of prions then stick together to form fibrous, protein deposits called amyloid plaques inside an infected animal’s brain and nervous system, leading to disease.

Prion disease can be challenging to diagnose because prions are not detectable with many tools used for disease agents like bacteria and viruses. Currently, the “gold standard” tests for CWD can only be done on tissues collected from a deer after it has died. These tests are both time- and labor-intensive and can miss low-grade infections. To help improve testing capabilities for CWD, we are building capacity for a new test for prions, Real-Time Quaking Induced Conversion (RT-QuIC) at the CWHL.

Young male white-tailed deer in open field. Deer often look healthy even when infected with CWD.

RT-QuIC testing takes advantage of the ability of CWD prions to convert normal proteins to misfolded prions. The test is done by combining normal proteins with a small amount of CWD prion and a dye that produces light when bound to amyloid plaques. This mixture is briefly shaken to help the CWD prions contact normal proteins. Then a picture is taken of the container to see if the dye bound to an amyloid plaque and produced light. Cycles of shaking and image collection are repeated many times. We can use the information about the amount of light found in the photographs after many cycles to tell if a sample contains CWD prions.

Importantly, RT-QuIC has potential to be faster and more sensitive than the current “gold standard” tests used to detect CWD prions. By improving test sensitivity, we may be able to use RT-QuIC to find CWD prions from tissue samples collected from live deer or even non-invasive samples like urine and feces. This new test would help us find infections faster, so we can prevent the spread of CWD through the deer herd.