The United States Department of Agriculture (USDA) has recently made changes in the procedures required for sample collection from cervids for chronic wasting disease (CWD) testing by immunohistochemistry. Ohio is considered free of CWD and has robust surveillance programs in captive and free-ranging deer. The Ohio ADD has tested over 8000 samples per year, for the last several years. The following changes are now required for veterinarians submitting samples to an approved laboratory for CWD testing, including submission of both fresh and formalin-fixed samples.
Call the ADDL with any questions or concerns at 614-728-6220.
Article written by Dr. Jeff Hayes, DVM, MS, ADDL Pathology Section Head
(10:1 ratio of formalin to tissue sample)
After removing the brainstem from the foramen magnum, ensure the proper obex sample (bifurcation or “V”) is preserved. Further trim the brainstem section by making a transverse cut ¾ inch in front of the “V” shape bifurcation and an equal distance behind the bifurcation. Place the trimmed obex into the formalin jar.
Medial Retropharyngeal Lymph Nodes (MRPLNs)
Remove each left and right MRPLN as done previously, now, longitudinally incise each lymph node. Place half of the left and half of the right node into the formalin jar, and the other halves into a whirl-pak bag (see below).
(collect samples in one labeled whirl-pak bag)
Place the rostral and distal pieces of brainstem in the labeled bag.
Retropharyngeal Lymph Nodes
Place the other halves of each node into the same bag.
ID Tags And Skin
Remove the official ID with a 1”X1” piece of ear attached for each animal sampled, place it in the labeled bag and submit with other fresh tissues. DO NOT PLACE IN FORMALIN.