State and Provincial Updates
Texas The following press release was issued on July 1, 2015 by the Texas Parks & Wildlife Department
Chronic Wasting Disease Detected in Medina County Captive Deer
AUSTIN – A two-year-old white-tailed deer in a Medina County deer breeding facility has been confirmed positive for Chronic Wasting Disease (CWD). This is the first case of CWD detected in captive white-tailed deer in Texas. CWD was first detected in Texas in 2012 in free-ranging mule deer in the Hueco Mountains in far West Texas.
The Medina County tissue samples submitted by the breeder facility in early June as part of routine deer mortality surveillance revealed the presence of CWD during testing at the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) in College Station. The National Veterinary Services Laboratory in Ames, Iowa, confirmed the findings on Tuesday, June 30. An epidemiological investigation to determine the extent of the disease, assess risks to Texas’ free ranging deer and protect the captive deer and elk breeding industry is being led by the Texas Animal Health Commission (TAHC), in coordination with the Texas Parks and Wildlife Department (TPWD) and U.S. Department of Agriculture’s Animal and Plant Health Inspection Service Veterinary Services (USDA/APHIS/VS).
Officials have taken immediate action to secure all cervids at the Medina County breeder facility with plans to conduct additional investigation for CWD. In addition, those breeder facilities that have received deer from the Medina County facility or shipped deer to that facility during the last two years are under movement restrictions and cannot move or release cervids at this time. TPWD is disallowing liberation of captive deer from all breeder facilities into the wild at this time pending further review. Additional measures to further minimize risk of CWD spreading into Texas’ free-ranging white-tailed deer herd, and to protect the captive deer breeding industry, will be considered.
“This is a terribly unfortunate development that we are committed to addressing as proactively, comprehensively, and expeditiously as possible. The health of our state’s wild and captive deer herds, as well as affiliated hunting, wildlife, and rural based economies, are vitally important to Texas hunters, communities, and landowners. As such, our primary objectives are to determine the source of the disease and to identify other deer breeding facilities and release sites that may have received deer from affected facilities,” said Carter Smith, TPWD Executive Director. “Working collaboratively with experts in the field we have developed protocols to address CWD, and our implementation efforts are already well under way.”
The TPWD and the TAHC CWD Management Plan will guide the State’s response to this incident. The plan was developed by the State’s CWD Task Force, which is comprised of deer and elk breeders, wildlife biologists, veterinarians and other animal-health experts from TPWD, TAHC, TVMDL, Department of State Health Services, Texas A&M College of Veterinary Medicine, and USDA.
Since 2002, the state has conducted surveillance throughout Texas for the disease. More than 34,000 samples collected from hunter-harvested and road kill deer have been tested for CWD. Although animal health and wildlife officials cannot say how long or to what extent the disease has been present in the Medina County deer breeding facility, the breeder has had an active CWD surveillance program since 2006 with no positives detected until now.
“We are working with experts at the local, state and federal level, to determine the extent of this disease, and respond appropriately to limit further transmission,” said Dr. Andy Schwartz, TAHC Epidemiologist and Assistant Executive Director. “Strong public awareness and the continued support of the cervid industry is paramount to the success of controlling CWD in Texas.”
The disease was first recognized in 1967 in captive mule deer in Colorado. CWD has also been documented in captive and/or free-ranging deer in 23 states and 2 Canadian provinces. CWD among cervids is a progressive, fatal disease that commonly results in altered behavior as a result of microscopic changes made to the brain of affected animals. An animal may carry the disease for years without outward indication, but in the latter stages, signs may include listlessness, lowering of the head, weight loss, repetitive walking in set patterns, and a lack of responsiveness. To date there is no evidence that CWD poses a risk to humans or non-cervids. However, as a precaution, the U.S. Centers for Disease Control and the World Health Organization recommend not to consume meat from infected animals.
More information on CWD can be found on TPWD’s website, www.tpwd.texas.gov/CWD or at the Chronic Wasting Disease Alliance website, www.cwd-info.org.
More information about the TAHC CWD program may be found at http://tahc.state.tx.us/animal_health/cwd/cwd.html.
Wisconsin The following press release was issued by the Wisconsin Department of Agriculture, Trade and Consumer Protection on June 24, 2015
CWD-positive white-tailed deer found on Eau Claire County farm MADISON – A white-tailed deer from a breeding farm in Eau Claire County has tested positive for chronic wasting disease (CWD), Wisconsin State Veterinarian Dr. Paul McGraw announced today. The National Veterinary Services Laboratory in Ames, Iowa, confirmed the test results.
The 7-year-old Eau Claire County doe, which died on the farm, was one of about 167 deer reported to be on the 12 acre farm, according to the farm’s March 2015 registration.
Samples were taken from the doe on June 8 in accordance with Wisconsin Department of Agriculture, Trade and Consumer Protection’s (DATCP’s) rules, which require testing of farm-raised deer and elk when they die or are killed.
McGraw quarantined the Eau Claire County herd, which stops movement of live deer from the property, except to slaughter. Disposition of the remaining deer will depend upon the outcome of the investigation. The DATCP Animal Health Division’s investigation will also examine the animal’s history and trace movements of deer onto and off the property to determine whether other herds may have been exposed to the CWD test-positive deer.
Recent Publications Quantitative assessment of prion infectivity in tissues and body fluids by real-time quaking-induced conversion Davin M. Henderson, Kristen A. Davenport, Nicholas J. Haley, Nathaniel D. Denkers, Candace K. Mathiason and Edward A. Hoover Journal of General Virology (2015) 96, 210-219. doi: 10.1099/vir.0.069906-0
Abstract: Prions are amyloid-forming proteins that cause transmissible spongiform encephalopathies through a process involving the templated conversion of the normal cellular prion protein (PrPC) to a pathogenic misfolded conformation. Templated conversion has been modelled in several in vitro assays, including serial protein misfolding amplification, amyloid seeding and real-time quaking-induced conversion (RT-QuIC). As RT-QuIC measures formation of amyloid fibrils in real-time, it can be used to estimate the rate of seeded conversion. Here, we used samples from deer infected with chronic wasting disease (CWD) in RT-QuIC to show that serial dilution of prion seed was linearly related to the rate of amyloid formation over a range of 10?3 to 10?8 ?g. We then used an amyloid formation rate standard curve derived from a bioassayed reference sample (CWD+ brain homogenate) to estimate the prion seed concentration and infectivity in tissues, body fluids and excreta. Using these methods, we estimated that urine and saliva from CWD-infected deer both contained 1–5 LD50 per 10 ml. Thus, over the 1–2 year course of an infection, a substantial environmental reservoir of CWD prion contamination accumulates.
Immediate and Ongoing Detection of Prions in the Blood of Hamsters and Deer following Oral, Nasal, or Blood Inoculations Alan M. Elder, Davin M. Henderson, Amy V. Nalls, Edward A. Hoover, Anthony E. Kincaid, Jason C. Bartz and Candace K. Mathiason
Journal of Virology 89:7421–7424 doi:10.1128/JVI.00760-15. Abstract: Infectious prions traverse epithelial barriers to gain access to the circulatory system, yet the temporal parameters of transepithelial transport and persistence in the blood over time remain unknown. We used whole-blood real-time quaking-induced conversion (wbRT-QuIC) to analyze whole blood collected from transmissible spongiform encephalopathy (TSE)-inoculated deer and hamsters throughout the incubation period for the presence of common prion protein-conversion competent amyloid (PrPC-CCA). We observed PrPC-CCA in the blood of TSE-inoculated hosts throughout the disease course from minutes postexposure to terminal disease. http://jvi.asm.org/content/early/2015/04/24/JVI.00760-15.abstract