Preliminary Findings on the Experimental Transmission of Chronic Wasting Disease Agent of Mule Deer to Cattle

This communication reports final observations on experimental transmission of chronic wasting disease (CWD) from mule deer to cattle by the intracerebral route. Thirteen calves were inoculated intracerebrally with brain suspension from mule deer naturally affected with CWD. Three other calves were kept as uninoculated controls. The experiment was terminated 6 years after inoculation. During that time, abnormal prion protein (PrPres) was demonstrated in the central nervous system (CNS) of 5 cattle by both immunohistochemistry and Western blot. However, microscopic lesions suggestive of spongiform encephalopathy (SE) in the brains of these PrPres-positive animals were subtle in 3 cases and absent in 2 cases. Analysis of the gene encoding bovine PRNP revealed homozygosity for alleles encoding 6 octapeptide repeats, serine (S) at codon 46, and S at codon 146 in all samples. Findings of this study show that although PrPres amplification occurred after direct inoculation into the brain, none of the affected animals had classic histopathologic lesions of SE. Furthermore, only 38% of the inoculated cattle demonstrated amplification of PrPres. Although intracerebral inoculation is an unnatural route of exposure, this experiment shows that CWD transmission in cattle could have long incubation periods (up to 5 years). This finding suggests that oral exposure of cattle to CWD agent, a more natural potential route of exposure, would require not only a much larger dose of inoculum but also may not result in amplification of PrPres within CNS tissues during the normal lifespan of cattle.

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Experimental Transmission of Chronic Wasting Disease (CWD) of Elk (Cervus elaphus nelsoni), White-tailed Deer (Odocoileus virginianus), and Mule Deer (Odocoileus hemionus hemionus) to White-tailed Deer by Intracerebral Route

Veterinary Pathology ◽

10.1354/vp.45-3-297 ◽

2008 ◽

Vol 45 (3) ◽

pp. 297-306 ◽

Cited By ~ 17

Author(s):

A. N. Hamir ◽

J. A. Richt ◽

J. M. Miller ◽

R. A. Kunkle ◽

S. M. Hall ◽

...

Keyword(s):

Odocoileus Virginianus ◽

Cervus Elaphus ◽

Chronic Wasting Disease ◽

Mule Deer ◽

Odocoileus Hemionus ◽

Wasting Disease ◽

Experimental Transmission ◽

Cervus Elaphus Nelsoni

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Tonsillar Biopsy Test for Chronic Wasting Disease: Two Sampling Approaches in Mule Deer and White-tailed Deer

Journal of Wildlife Diseases ◽

10.7589/0090-3558-41.4.820 ◽

2005 ◽

Vol 41 (4) ◽

pp. 820-824 ◽

Cited By ~ 5

Author(s):

Krysten L. Schuler ◽

Jonathan A. Jenks ◽

Christopher S. DePerno ◽

Margaret A. Wild ◽

Christopher C. Swanson

Keyword(s):

Chronic Wasting Disease ◽

Mule Deer ◽

Wasting Disease

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Differing Neurohistologic Images of Scrapie, Transmissible Mink Encephalopathy, and Chronic Wasting Disease of Mule Deer and Elk

Bovine Spongiform Encephalopathy ◽

10.1007/978-1-4612-2406-8_11 ◽

1996 ◽

pp. 122-137 ◽

Cited By ~ 4

Author(s):

William J. Hadlow

Keyword(s):

Chronic Wasting Disease ◽

Mule Deer ◽

Wasting Disease ◽

Transmissible Mink Encephalopathy

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Failure To Detect Prion Infectivity in Ticks following Prion-Infected Blood Meal

mSphere ◽

10.1128/msphere.00741-20 ◽

2020 ◽

Vol 5 (5) ◽

Author(s):

Ronald A. Shikiya ◽

Anthony E. Kincaid ◽

Jason C. Bartz ◽

Travis J. Bourret

Keyword(s):

Prion Disease ◽

Blood Meal ◽

Red Deer ◽

Chronic Wasting Disease ◽

Mule Deer ◽

Geographic Range ◽

Lymphoid Tissues ◽

Wasting Disease ◽

Prion Infection ◽

Prion Infectivity

ABSTRACT Chronic wasting disease (CWD) is an emerging and fatal contagious prion disease that affects cervids, including mule deer, white-tailed deer, black-tailed deer, red deer reindeer, elk, and moose. CWD prions are widely distributed throughout the bodies of CWD-infected animals and are found in the nervous system, lymphoid tissues, muscle, blood, urine, feces, and antler velvet. The mechanism of CWD transmission in natural settings is unknown. Potential mechanisms of transmission include horizontal, maternal, or environmental routes. Due to the presence of prions in the blood of CWD-infected animals, the potential exists for invertebrates that feed on mammalian blood to contribute to the transmission of CWD. The geographic range of the Rocky Mountain Wood tick, Dermancentor andersoni, overlaps with CWD throughout the northwest United States and southwest Canada, raising the possibility that D. andersoni parasitization of cervids may be involved in CWD transmission. We investigated this possibility by examining the blood meal of D. andersoni that fed upon prion-infected hamsters for the presence of prion infectivity by animal bioassay. None of the hamsters inoculated with a D. andersoni blood meal that had been ingested from prion-infected hamsters developed clinical signs of prion disease or had evidence for a subclinical prion infection. Overall, the data do not demonstrate a role for D. andersoni in the transmission of prion disease. IMPORTANCE Chronic wasting disease (CWD) is an emerging prion disease that affects cervids, including mule deer, white-tailed deer, black-tailed deer, red deer reindeer, elk, and moose. The mechanism of CWD transmission in unknown. Due to the presence of prions in the blood of CWD-infected animals, it is possible for invertebrates that feed on cervid blood to contribute to the transmission of CWD. We examined the blood meal of D. andersoni, a tick with a similar geographic range as cervids, that fed upon prion-infected hamsters for the presence of prion infectivity by animal bioassay. None of the D. andersoni blood meals that had been ingested from prion-infected hamsters yielded evidence of prion infection. Overall, the data do not support a role of D. andersoni in the transmission of prion disease.

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Use of environmental sites by mule deer: a proxy for relative risk of chronic wasting disease exposure and transmission

Ecosphere ◽

10.1002/ecs2.2055 ◽

2018 ◽

Vol 9 (1) ◽

Cited By ~ 4

Author(s):

María Fernanda Mejía‐Salazar ◽

Cheryl L. Waldner ◽

Yeen Ten Hwang ◽

Trent K. Bollinger

Keyword(s):

Relative Risk ◽

Chronic Wasting Disease ◽

Mule Deer ◽

Wasting Disease ◽

Disease Exposure

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Ultrastructural neuropathology of chronic wasting disease in captive mule deer

Acta Neuropathologica ◽

10.1007/bf00334456 ◽

1993 ◽

Vol 85 (4) ◽

pp. 437-444 ◽

Cited By ~ 9

Author(s):

Don C. Guiroy ◽

Elizabeth S. Williams ◽

Pawel P. Liberski ◽

Ikuro Wakayama ◽

D. Carleton Gajdusek

Keyword(s):

Chronic Wasting Disease ◽

Mule Deer ◽

Wasting Disease

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Experimental Transmission of the Chronic Wasting Disease Agent to Swine after Oral or Intracranial Inoculation

Journal of Virology ◽

10.1128/jvi.00926-17 ◽

2017 ◽

Vol 91 (19) ◽

Cited By ~ 14

Author(s):

S. Jo Moore ◽

M. Heather West Greenlee ◽

Naveen Kondru ◽

Sireesha Manne ◽

Jodi D. Smith ◽

...

Keyword(s):

Prion Protein ◽

Prion Disease ◽

Chronic Wasting Disease ◽

Mouse Bioassay ◽

Lymphoid Tissues ◽

Species Barrier ◽

Wasting Disease ◽

Disease Agent ◽

Domestic Swine

ABSTRACT Chronic wasting disease (CWD) is a naturally occurring, fatal neurodegenerative disease of cervids. The potential for swine to serve as hosts for the agent of CWD is unknown. The purpose of this study was to investigate the susceptibility of swine to the CWD agent following experimental oral or intracranial inoculation. Crossbred piglets were assigned to three groups, intracranially inoculated (n = 20), orally inoculated (n = 19), and noninoculated (n = 9). At approximately the age at which commercial pigs reach market weight, half of the pigs in each group were culled (“market weight” groups). The remaining pigs (“aged” groups) were allowed to incubate for up to 73 months postinoculation (mpi). Tissues collected at necropsy were examined for disease-associated prion protein (PrPSc) by Western blotting (WB), antigen capture enzyme immunoassay (EIA), immunohistochemistry (IHC), and in vitro real-time quaking-induced conversion (RT-QuIC). Brain samples from selected pigs were also bioassayed in mice expressing porcine prion protein. Four intracranially inoculated aged pigs and one orally inoculated aged pig were positive by EIA, IHC, and/or WB. By RT-QuIC, PrPSc was detected in lymphoid and/or brain tissue from one or more pigs in each inoculated group. The bioassay was positive in four out of five pigs assayed. This study demonstrates that pigs can support low-level amplification of CWD prions, although the species barrier to CWD infection is relatively high. However, detection of infectivity in orally inoculated pigs with a mouse bioassay raises the possibility that naturally exposed pigs could act as a reservoir of CWD infectivity. IMPORTANCE We challenged domestic swine with the chronic wasting disease agent by inoculation directly into the brain (intracranially) or by oral gavage (orally). Disease-associated prion protein (PrPSc) was detected in brain and lymphoid tissues from intracranially and orally inoculated pigs as early as 8 months of age (6 months postinoculation). Only one pig developed clinical neurologic signs suggestive of prion disease. The amount of PrPSc in the brains and lymphoid tissues of positive pigs was small, especially in orally inoculated pigs. Regardless, positive results obtained with orally inoculated pigs suggest that it may be possible for swine to serve as a reservoir for prion disease under natural conditions.

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