Ticks harbor and excrete chronic wasting disease prions
Chronic wasting disease (CWD) is a fatal neurodegenerative disease caused by infectious prions (PrPCWD) affecting cervids. Circulating PrPCWD in blood may pose a risk for indirect transmission by way of hematophagous ectoparasites acting as mechanical vectors. Cervids can carry high tick infestations and exhibit allogrooming, a common tick defense strategy between conspecifics. Ingestion of ticks during allogrooming may expose naïve animals to CWD, if ticks harbor PrPCWD. This study investigates whether ticks can harbor transmission-relevant quantities of PrPCWD by combining experimental tick feeding trials and evaluation of ticks from free-ranging white-tailed deer (Odocoileus virginianus). Using the real-time quaking-induced conversion (RT-QuIC) assay, we show that black-legged ticks (Ixodes scapularis) fed PrPCWD-spiked blood using artificial membranes ingest and excrete PrPCWD. Combining results of RT-QuIC and protein misfolding cyclic amplification, we detected seeding activity from 6 of 15 (40%) pooled tick samples collected from wild CWD-infected white-tailed deer. Seeding activities in ticks were analogous to 10–1000 ng of CWD-positive retropharyngeal lymph node collected from deer upon which they were feeding. Estimates revealed a median infectious dose range of 0.3–42.4 per tick, suggesting that ticks can take up transmission-relevant amounts of PrPCWD and may pose a CWD risk to cervids.
Citation Information
Publication Year | 2023 |
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Title | Ticks harbor and excrete chronic wasting disease prions |
DOI | 10.1038/s41598-023-34308-3 |
Authors | H. N. Inzalaco, F. Bravo-Risi, R. Morales, D. P. Walsh, D. J. Storm, J. A. Pedersen, Wendy Christine Turner, S. S. Lichtenbergh |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Scientific Reports |
Index ID | 70257339 |
Record Source | USGS Publications Warehouse |
USGS Organization | Coop Res Unit Leetown |