Chronic wasting disease

Chronic wasting disease
Name	Chronic wasting disease
Symptoms	weight loss, behavioral changes, ataxia
Onset	variable
Causes	prion protein misfolding
Risks	cervid populations, captive facilities
Diagnosis	biopsy, immunohistochemistry, ELISA, RT-QuIC
Treatment	none; supportive care
Prognosis	fatal

Chronic wasting disease is a progressive, fatal prion disease affecting cervids such as White-tailed deer, Mule deer, Elk, and Moose. First identified in the late 20th century in North America, it has since been detected in wild and captive populations across multiple regions, prompting international responses from agencies like the United States Department of Agriculture, Canadian Food Inspection Agency, and the World Organisation for Animal Health. Research from institutions including Centers for Disease Control and Prevention, Pennsylvania State University, University of Saskatchewan, Colorado State University, and Montana State University informs surveillance, control, and risk assessment strategies.

Overview

CWD is one of several transmissible spongiform encephalopathies alongside Bovine spongiform encephalopathy, Creutzfeldt–Jakob disease, and Scrapie. Surveillance programs by entities such as the Alaska Department of Fish and Game, Minnesota Department of Natural Resources, Ontario Ministry of Natural Resources and Forestry, New York State Department of Environmental Conservation, and provincial or state agencies track prevalence and geographic spread. International coordination involves organizations including the World Health Organization, European Food Safety Authority, and the OIE World Organisation for Animal Health. Management intersects with stakeholders like the National Wildlife Federation, Safari Club International, Ducks Unlimited, and regional hunting associations.

Cause and Pathophysiology

CWD is caused by misfolded prion proteins (PrP^Sc) derived from the normal cellular prion protein (PrP^C). Research groups at Rocky Mountain Laboratories, Iowa State University, Texas A&M University, University of Minnesota, and University of Wisconsin–Madison have characterized neurodegeneration, spongiform change, and gliosis in affected brains. Laboratory methods developed at facilities such as the National Institutes of Health, Fred Hutchinson Cancer Center, and Los Alamos National Laboratory include western blotting, immunohistochemistry, ELISA, and RT-QuIC assays. Molecular studies reference polymorphisms described in work from University of Cambridge, Harvard University, and University of Oxford to explain host susceptibility and incubation period variability.

Transmission and Epidemiology

Transmission occurs via horizontal routes, environmental contamination, and potential maternal routes; infectious prions shed in saliva, urine, feces, and decomposing carcasses persist in soil and plants. Field studies by researchers at Montana Fish, Wildlife & Parks, South Dakota Game, Fish and Parks, Wyoming Game and Fish Department, Wisconsin Department of Natural Resources, and academic teams at University of Wyoming and Michigan State University map spatial spread. Outbreak responses have involved policy actions by the Interstate Fishery and Wildlife Agencies', state legislatures such as the Colorado General Assembly and Montana Legislature, and federal coordination through the US Fish and Wildlife Service and USDA Animal and Plant Health Inspection Service. International detections prompted action from agencies like the Norwegian Veterinary Institute, Swedish University of Agricultural Sciences, and Korea Centers for Disease Control and Prevention.

Clinical Signs and Diagnosis

Affected cervids exhibit progressive weight loss, behavioral changes, drooling, ataxia, and lowered awareness; clinical progression mirrors descriptions from veterinary centers including Mayo Clinic, Cummings School of Veterinary Medicine at Tufts University, and College of Veterinary Medicine at Cornell University. Antemortem diagnosis uses tonsil or rectoanal mucosa-associated lymphoid tissue biopsies evaluated by laboratories such as Michigan State University Veterinary Diagnostic Laboratory, Washington Animal Disease Diagnostic Laboratory, and Oregon State University Veterinary Diagnostic Laboratory. Postmortem confirmation employs brainstem obex testing with immunohistochemistry and biochemical assays refined by teams at University of Alberta, University of Calgary, and National Veterinary Services Laboratories.

Management and Control Measures

Control measures include targeted surveillance, testing of hunter-harvested and road-kill animals, movement restrictions for captive cervids, herd depopulation in affected facilities, and disposal protocols guided by agencies like the USDA APHIS, Environment and Climate Change Canada, Alberta Agriculture and Forestry, and state wildlife departments. Research into soil remediation, plant uptake, and prion degradation involves collaboration among Lawrence Livermore National Laboratory, Argonne National Laboratory, US Geological Survey, and academic groups at University of California, Davis and University of British Columbia. Policy tools include import/export rules enforced by bodies such as the European Commission, Canadian Food Inspection Agency, and state regulatory frameworks like the Montana Department of Livestock statutes. Stakeholders including hunting organizations, conservation NGOs, indigenous authorities such as the Nez Perce Tribe, Blackfeet Nation, and provincial first nations collaborate on local response plans.

Public Health and Zoonotic Risk

Public health agencies such as the Centers for Disease Control and Prevention, Public Health Agency of Canada, European Centre for Disease Prevention and Control, and Norwegian Institute of Public Health evaluate zoonotic potential. While no confirmed cases of transmission to humans have been documented, agencies advise precautions for hunters and meat processors, including testing of harvested animals and following guidance from institutions like the Food and Drug Administration, Health Canada, and state health departments. Comparative studies reference human prion diseases investigated at National Prion Clinic (UK), MRC Prion Unit, and University College London to assess species barriers. Research priorities involve long-term surveillance coordinated by bodies such as the Centers for Disease Control and Prevention Chronic Wasting Disease Program, academic consortia, and international partners to refine risk estimates and inform public guidance.

Category:Prion diseases