Chronic Wasting Disease (CWD) is a neurological disease found in white-tailed deer in Iowa and other members of the deer family in agriculture or across the country. The Centers for Disease Control and Prevention advise against the consumption of animals that test positive for the disease because of the potential risk of the disease to human consumers. There is no confirmed case of CWD affecting humans or pets, but scientists encourage caution to reduce possible transmission. This page is intended to help hunters submit a CWD sample from their harvest to submit for testing at a certified laboratory, including Iowa State University's Veterinary Diagnostic Laboratory.
Sampling
Diagnostic testing for CWD is done with a sample from a lymph node in the deck of deer (the medial retropharyngeal lymph node). These are like the swollen lymph nodes a doctor may feel for around your neck when you're sick. The infectious agent of CWD (called a misfolded prion) accumulates in lymph tissue and laboratory tests are designed to detect it in animals with the disease well before they appear sick. Note that some species, such as elk, require additional tissue samples other than the lymph node for diagnostic testing. Be sure to check with your diagnostic lab to confirm the right samples needed before your hunt. The instructions on this page are for wild white-tailed deer.
Step 1: Make a deep incision one inch below the jaw to the spine
Locate the end of the jaw on the animal and go back about one inch. Make a deep cut with a sharp knife like a boning or fillet knife. Extend this cut all the way through the windpipe. Stop just before you hit the spine.
Step 2: Search behind and on each side of the trachea for the lymph nodes
Feel and look for the lymph nodes. They will sit behind the windpipe and beside the tan, feathery salivary glands. They have a firm texture and can range in size from a marble to a small egg. They are often surrounded by several small purple structures called hemal nodes or “blueberries.”
Step 3: Preserve the lymph nodes in clearly labeled bags
Put each lymph node in a separate bag labeled with information about the deer (e.g., location of harvest, tag number, date, sex). Place the lymph nodes and bags in your freezer before delivering or shipping them to the lab.
Disinfect your knife by rinsing off the debris and then soaking it in a 40% household bleach solution (2 parts bleach, 3 parts water) for five minutes.
Additional considerations
- Sampling deer that you plan to taxidermy can be more difficult because you can't make the first incision into the hide. Deer destined for taxidermy should be sampled after they are caped out.
- Lymph nodes can take many different shapes and sizes (and their shape and size has nothing to do with the deer's CWD status)
- To confirm you sampled the right tissue, cut through it and look for a uniform, smooth texture. Other tissues in the region (such as salivary gland) will be less firm than lymph tissue.
Testing
Once you have you lymph tissues you can deliver or ship them to the Iowa State University Veterinary Diagnostic Laboratory for testing.
- First complete the Submission Form at the VDL at the link below
CWD Submission Form at the Veterinary Diagnostic Laboratory
- You will enter information about your deer including the sex, age class (see below), and location of harvest.
- Once you submit your online payment you will receive a 6-digit “Web ID” number. This Web ID will link your information to the tissue sample received at the lab.
Deliver both lymph nodes in a single plastic bag labeled with your Web ID. You can ship samples or drop them off in person.
To ship, address a reinforced envelope, bubble mailer, or other shipping container to the address below. Ship as early within a week as possible. Ice packs are not required.
Veterinary Diagnostic Laboratory
Iowa State University
1937 Christensen Drive
Ames, IA 50011-1100- Once the sample is processed, you will get an email from the laboratory indicating if the sample tested positive or negative.
- Negative results will say "The sample came back as 'Not Detected.'"
- Positive results will be confirmed with additional testing at the National Veterinary Services Laboratories in Ames. You will likely get a call from the lab if the test comes back positive.
Diagnostic tests at the laboratory are conducted through a series of reactions called the enzyme-linked immunosorbent assay (ELISA), which uses antibodies to detect the presence of disease-associated proteins in a sample.
Age determination
Some sample submission interfaces require reporting the age of the deer that the sample came from. Deer are classified into three age categories for monitoring purposes: fawns, ye. You can determine the age classification of your deer by inspecting the pattern of tooth eruption in the lower jaw.
