Image by Jack Bulmer from Pixabay.

August 1, 2023

COVID-19 and Wildlife: An interdisciplinary effort to disease surveillance in deer

Did you know that deer could become infected with COVID-19? It came as a surprise to me, too (Figure 1). Recently, USDA Agricultural Research Service revealed that infected deer, even if they show no symptoms, can shed the infectious virus for 2 to 5 days after infection and transmit it to other non-infected deer1. Identifying mammal species that can act as intermediate hosts for COVID-19 is essential to understanding the effect of COVID-19 spillovers from humans to wildlife – especially for threatened and endangered species2. Recognizing gaps in knowledge regarding COVID infection in white-tailed deer, the USDA Wildlife Services (USDA-WS) decided to survey SARS-CoV-2 in deer populations across the United States.

A diagram showing possible infection routes between white-tailed deer, livestock or wildlife, and humans through direct or indirect contact.
Figure 1. Potential transmission pathways of SARS-CoV-2 between deer, humans, and other animals. Graphic by Joey He.

As a member of the Wildlife Veterinary Epidemiology Laboratory (WVEL) at the Illinois Natural History Survey (INHS), I was thrilled for the opportunity to assist USDA-WS with the sampling of Illinois wild white-tailed deer. With colleagues from the Forbes Biological Station at INHS, Western Illinois, and Loyola Universities, WVEL organized and deployed a team to carry out the USDA field protocols for SARS-CoV-2 sampling during the first and second Illinois white-tailed deer firearm seasons of 2022. Our laboratory coordinated with the Illinois Department of Natural Resources (IDNR) and USDA-WS to collect COVID samples from hunter-harvested white-tailed deer alongside IDNR operations. We focused on Carroll, Jo Daviess and Stephenson counties where the IDNR had deer check stations to conduct Chronic Wasting Disease (CWD) monitoring and surveillance.

The evening had settled in by the time we arrived in Freeport. Despite the late hour, our excitement was palpable. After enjoying a light dinner, we gathered to pack our essential tools and kits for the upcoming days. Eventually, exhaustion caught up with us, and we all returned to our rooms to rest before the exciting adventure awaiting us the following day. With the break of dawn, we embarked on our journey to the Jo Daviess check station. Upon our arrival, we were greeted by a warm, blazing bonfire fueled by wood often supplied by hunters – a welcoming touch considering that the temperatures were around 28 degrees F, and we were going to work outside all day and past sunset. The IDNR biologists had already begun their day’s work. Wasting no time, we swiftly organized our trucks and tool kits, split into groups, assigned roles, and joined and followed the IDNR CWD-sampling teams. Upon receipt of the hunter’s approval, we collected COVID diagnostic samples (Figure 2) from deer sampled for CWD.

An illustrated  graphic showing a female and male deer sampled for SARS-CoV-2  by nose swab, oral swab or blood sample.
Figure 2. Methodology of how nose, mouth, and blood samples were collected for SARS-CoV-2 detection from hunter harvested white-tailed deer. Created by Sofia Mateus.

It didn’t take long before our first deer arrived. I felt nervous as it was a completely new experience for me. It was my first opportunity to participate in fieldwork and to work with IDNR biologists and hunters. I carefully observed the biologists to see how they navigated the conversations, seeking to learn from their expertise. Hunters welcomed the presence of the research team and willingly participated in the surveillance of CWD. When we identified ourselves and asked hunters if they would let us collect samples for COVID-19 surveillance in deer, they expressed genuine kindness and patience with our team, whether or not they allowed us to sample their deer. Some added a touch of humor and asked us to swab them. Some engaged in conversations about the SARS-CoV-2 virus and eagerly shared what they had read. Many shared stories about their hunting experiences and why they hunt. The camaraderie between the COVID research team and the hunters grew stronger with each interaction. Engaging with the hunters gave us insights into the regulated hunting culture and hunter’s perspectives. We learned that hunted deer serve as a food source for the family, that life lessons are taught and passed down from generation to generation during hunting efforts, that bonds are built, and that family traditions can build knowledge about conservation and help control the white-tailed deer population. Moreover, we had the opportunity to share the importance of their efforts for educating students and for research efforts as they participated and cooperated with our work.

Additionally, witnessing the IDNR biologists’ extensive work in collecting CWD diagnostic, surveillance, and genetic samples, and managing and coordinating efforts with the hunters and stakeholders, was impressive. The biologists braved the cold and snow, remaining outdoors from dawn till dusk. During peak hours, vehicles kept streaming in, leaving no time for rest. Jameson Mori, a post-doctoral research associate in our lab, said, “A lot of planning and work goes into the CWD check stations, and IDNR handles many questions and concerns from the public about the program.”

The biting cold was so intense that I could barely feel my hands. After this experience, my respect for regulated hunting, IDNR, and USDA biologists and their dedication to conservation, disease surveillance, and management grew exponentially. I felt privileged to contribute and was happy to be part of the COVID surveillance process.

My colleagues also had a unique perspective on this remarkable experience (Figure 3).

A collage of three photos of researchers conducting SARS-CoV-2 sampling of white-tailed deer at Illinois deer check stations with five quotes about their experiences.
Figure 3. The COVID sampling team was cold but happy and thankful for the experience and the learning opportunity from hunters, IDNR and USDA biologists, and colleagues.
  • Sara P. Villazan, a graduate student from Western Illinois University, expressed, “I feel that I bring science closer to the community by cooperating with hunters and their families.”
  • Nicole Pietrunti, a graduate student from our lab, reflected, “I was inspired by the youngsters we met who were being mentored by family or friends to hunt deer. I was reminded of the value of hunting as a family tradition and a means of community-building.”
  • Sofia Mateus, an undergraduate student from Loyola University, expressed her delight, saying, “I was thrilled to witness the hunters’ pride in responsibly managing Illinois deer populations while also harboring a deep love and appreciation for nature.”

Overall, it was a humbling experience to witness the mutual respect and cooperation that flourished in this shared effort as we built our understanding of CWD and COVID-19 in white-tailed. The experience allowed me to learn from biologists, colleagues, and hunters, their families and friends, who deeply care for the conservation of natural resources; it was inspiring and reenergizing to see the efforts of agencies, universities, and hunters coming together toward a common goal. We sincerely thank all the members of the Forbes Biological Station, Western Illinois University, and Loyola University for joining us on short notice for this COVID-19 Surveillance project. We are also grateful to the USDA Wildlife Services for granting us the opportunity to participate in this surveillance effort. A special thanks to the hunters for sharing their experiences with us, their collaboration, and valuable insights. Lastly, we thank the IDNR for their invaluable support, dedicated efforts and willingness to teach us about their operations.


1) Palmer, M. V., Martins, M., Falkenberg, S., Buckley, A., Caserta, L. C., Mitchell, P. K., … & Diel, D. G. (2021). Susceptibility of white-tailed deer (Odocoileus virginianus) to SARS-CoV-2. Journal of Virology, 95(11), e00083-21.
2) Damas, J., Hughes, G. M., Keough, K. C., Painter, C. A., Persky, N. S., Corbo, M., … & Lewin, H. A. (2020). Broad host range of SARS-CoV-2 predicted by comparative and structural analysis of ACE2 in vertebrates. Proceedings of the National Academy of Sciences, 117(36), 232311-22322.

Joey He is an undergraduate majoring in integrative biology at the University of Illinois at Urbana-Champaign. She is currently in her senior year. Joey is a member of the Wildlife Veterinary Epidemiology Laboratory, where she works as an undergraduate researcher.

He would like to acknowledge Nelda A. Rivera, Evan London, Jameson Mori and Nohra Mateus-Pinilla, who helped with the sampling effort and writing of the article.

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