This video provides a brief overview of different pathways of CWD infection to cervid farms, including direct and indirect contact exposures from infected wild and farmed cervids.
Video transcript
Narrator (Voiceover):
Chronic wasting disease, or CWD, is a fatal disease that affects cervids.
It’s caused when normal prion proteins misfold, eventually leading to brain damage and death.
Infectious CWD prion proteins (hereafter called prions) can be spread through saliva, blood, feces, urine, antler velvet, and carcasses of infected cervids. Once infected, deer are contagious to other cervids by shedding prions before they appear sick. In the environment, prions remain infectious for a long time and are resistant to many disinfectants.
CWD can spread through direct and indirect contact.
Direct contact occurs anytime a non-infected cervid has physical contact with an infected cervid, for example through licking.
Indirect contact occurs when an infected cervid sheds prions into the environment or on equipment and then a non-infected cervid comes in contact with those prions.
Transmission of CWD from other farmed cervids also occurs directly or indirectly.
Bringing a healthy looking, but infected cervid into a herd can result in direct spread of CWD.
Because CWD symptoms can take a long time to appear, testing surveillance is required on all farmed cervid operations. Currently, these tests can only be performed on deceased animals.
Indirect contact could occur through sharing of materials contaminated with prions from an infected cervid farm.
Infected wild cervids may also be a source of CWD for farmed cervids.
When wild deer have direct contact with farmed deer, CWD may spread between them. This could occur through fencing breaches, or infrequently from contact through fences.
Indirect contact occurs through environmental contamination by prions shed from infected wild cervids or their carcasses.
Scavengers or birds who eat these carcasses may bring prions into your herd on their body or their feces.
There is potential for indirect contact through contaminated feeds or water. Plants can up-take prions shed by infected animals, harvesting feed from a known CWD location or sharing water sources may spread the prions.
If hunting in an area where CWD is endemic, infected soil and other organic material from that area can be brought back on vehicles, boots, clothing, or other hunting equipment.
CWD could also be spread through contact with an untested infected carcass brought back from hunting or for taxidermy.
Disposing of carcasses or waste in a pile near your herd can attract scavengers or birds.
All these different routes of CWD transmission can put your herd at risk.
See video 8 in this series to identify areas of potential exposure on your farm!
Credits
This video was developed through collaboration between the Pennsylvania Department of Agriculture and the University of Minnesota College of Veterinary Medicine, and produced for the Pennsylvania Department of Agriculture under USDA APHIS Cooperative Agreement AP22VSSPRS00C157 “CWD Training, Outreach, and Producer Education Program.”