RT-QuIC detection of chronic wasting disease prion in platelet samples of white-tailed deer

Estela Kobashigawa; Sherri Russell; Michael Z Zhang; Emily A Sinnott; Michael Connolly; Shuping Zhang

doi:10.1186/s12917-024-04005-y

RT-QuIC detection of chronic wasting disease prion in platelet samples of white-tailed deer

BMC Vet Res. 2024 Apr 23;20(1):152. doi: 10.1186/s12917-024-04005-y.

Authors

Estela Kobashigawa^{1

2}, Sherri Russell³, Michael Z Zhang^{1

2}, Emily A Sinnott³, Michael Connolly⁴, Shuping Zhang^{5

6}

Affiliations

¹ Veterinary Medical Diagnostic Laboratory, College of Veterinary Medicine, University of Missouri, 901 E. Campus Loop, Columbia, MO, USA.
² Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, 901 E. Campus Loop, Columbia, MO, USA.
³ Missouri Department of Conservation, 2901 W Truman Blvd, Jefferson City, MO, USA.
⁴ The Molecular Foundry, Lawrence Berkeley National Laboratory, 67 Cyclotron Rd, Berkeley, CA, USA.
⁵ Veterinary Medical Diagnostic Laboratory, College of Veterinary Medicine, University of Missouri, 901 E. Campus Loop, Columbia, MO, USA. zhangshup@missouri.edu.
⁶ Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, 901 E. Campus Loop, Columbia, MO, USA. zhangshup@missouri.edu.

Abstract

Background: Chronic wasting disease (CWD) is a prion disease of captive and free-ranging cervids. Currently, a definitive diagnosis of CWD relies on immunohistochemistry detection of PrP^Sc in the obex and retropharyngeal lymph node (RPLN) of the affected cervids. For high-throughput screening of CWD in wild cervids, RPLN samples are tested by ELISA followed by IHC confirmation of positive results. Recently, real-time quacking-induced conversion (RT-QuIC) has been used to detect CWD positivity in various types of samples. To develop a blood RT-QuIC assay suitable for CWD diagnosis, this study evaluated the assay sensitivity and specificity with and without ASR1-based preanalytical enrichment and NaI as the main ionic component in assay buffer.

Results: A total of 23 platelet samples derived from CWD-positive deer (ELISA + /IHC +) and 30 platelet samples from CWD-negative (ELISA-) deer were tested. The diagnostic sensitivity was 43.48% (NaCl), 65.22% (NaI), 60.87% (NaCl-ASR1) or 82.61% (NaI-ASR1). The diagnostic specificity was 96.67% (NaCl), 100% (NaI), 100% (NaCl-ASR1), or 96.67% (NaI-ASR1). The probability of detecting CWD prion in platelet samples derived from CWD-positive deer was 0.924 (95% CRI: 0.714, 0.989) under NaI-ASR1 experimental condition and 0.530 (95% CRI: 0.156, 0.890) under NaCl alone condition. The rate of amyloid formation (RFA) was greatest under the NaI-ASR1 condition at 10^-2 (0.01491, 95% CRI: 0.00675, 0.03384) and 10^-3 (0.00629, 95% CRI: 0.00283, 0.01410) sample dilution levels.

Conclusions: Incorporation of ASR1-based preanalytical enrichment and NaI as the main ionic component significantly improved the sensitivity of CWD RT-QuIC on deer platelet samples. Blood test by the improved RT-QuIC assay may be used for antemortem and postmortem diagnosis of CWD.

Keywords: CWD; Deer; Platelet; Probability; RAF; RT-QuIC; Sensitivity; Specificity.

MeSH terms

Animals
Blood Platelets* / chemistry
Deer* / blood
Enzyme-Linked Immunosorbent Assay / veterinary
Prions / blood
Sensitivity and Specificity*
Wasting Disease, Chronic* / blood
Wasting Disease, Chronic* / diagnosis

Substances

Prions