SPOKANE – The Washington Department of Fish and Wildlife (WDFW) received a private testing company report reflecting a positive chronic wasting disease (CWD) test result from a mule deer harvested in game management unit (GMU) 101 in Ferry County. Additional testing of the deer by WDFW was inconclusive for CWD.
The United States Department of Agriculture (USDA) and WDFW don’t currently recognize commercial CWD tests as an officially validated test for CWD detection. This is the first known use of this unapproved test in Washington, potentially the first report of the fatal disease in that unit, and the first possible case of CWD in mule deer in Washington state.
“Even though these results come from an unapproved test, we are doing our due diligence and investigating further to gain more information about this possible detection” said Dr. Kristin Mansfield, WDFW’s state wildlife veterinarian.
An individual harvested the buck in October and transported it outside of WDFW’s Eastern Region transport restriction zone without submitting CWD samples to WDFW for testing. Instead, the hunter submitted a sample of muscle to a private laboratory that offers testing for CWD. A WDFW Police investigation determined that the individual attempted, in good faith, to comply with the CWD rules and there was no evidence of criminal intent in this case.
The hunter saved a sample of brain tissue, which WDFW submitted to the Washington Animal Disease Diagnostic Laboratory (WADDL) after the private laboratory reported a positive result from the muscle sample. WADDL didn’t detect any prions (the misfolded proteins that cause CWD) in the brain tissue sample. However, because the submitted sample lacked the part of the brain (brainstem) required for official CWD testing, this result is inconclusive.
WDFW considers CWD test results from private laboratories inconclusive due to unknown testing accuracy and other impacting factors, such as the tissue sampled (e.g. muscle versus lymph node or brainstem) and stage of CWD infection. Only tests of specific lymph nodes or the brainstem performed by USDA-approved veterinary diagnostic laboratories such as WADDL, are standardized and validated for CWD detection and surveillance. For this reason, hunters are required by rule to submit the head or appropriate lymph node sample from their harvest to WDFW in areas where sampling is mandatory. Currently, this includes all 100-series GMUs in Washington.
Hunters may choose to send samples to third-party testing companies in addition to mandatory submission to WDFW, but those tests do not replace the requirement for approved sample submission to WDFW.
“This case underscores how important it is for hunters to follow the Department’s CWD sampling requirements and transport restrictions,” said Mansfield. “These rules are necessary to provide managers with credible and actionable information, limit the disease’s spread, and ultimately minimize its impact to our state’s deer, elk, and moose populations.”
WDFW has communicated this result with area tribes and British Columbia officials due to the proximity of this CWD report to their jurisdictions.
To date, WDFW has confirmed eight cases of CWD in Washington, in addition to this potential case. Confirmed cases are documented on WDFW’s CWD webpage, along with extensive information on this disease and existing rules regarding CWD sampling and carcass transportation.
WDFW works to preserve, protect, and perpetuate fish, wildlife, and ecosystems while providing sustainable fish and wildlife recreational and commercial opportunities.