Researchers experiencing success in first oral anthrax vaccine tests in white-tailed deer

Walt Cook, DVM, PhD (Image courtesy of Jason Nitsch ’14/College of Veterinary Medicine and Biomedical Sciences)

Texas A&M College of Veterinary Medicine and Biomedical Sciences (VMBS) researchers shared they are closer to creating an oral vaccine for anthrax after a recent study showed an immune response in white-tailed deer. The development of this oral vaccine will combat anthrax infections in wild animal population in an easier way for all.

“All mammals are susceptible to anthrax to some degree or another,” said Walt Cook, PhD, DVM, a clinical assistant professor in the VMBS’ Department of Veterinary Pathobiology (VTPB), in an organizational release.¹ “Ranchers who live in areas that are prone to having anthrax are able to give vaccinations to their herds as part of their routine preventative medical care, but that’s impossible to do with wild animals.”

According to the release,¹ inoculating wild deer populations against anthrax is crucial because if they are not protected, they contribute to outbreaks of the deadly bacteria. For animals that had anthrax and die, exposure to oxygen causes the bacteria to release the anthrax spores as the carcass decomposes. These spores can then infect another animal that breathes in bits of soil or ingests contaminated water or plants.

“In the right conditions, those spores can remain active in the soil for decades or even hundreds of years,” Cook said.¹ “Once it’s in the soil, it’s very difficult to remove, so controlling anthrax spore formation is essential.”

The goal of this project at VMBS is for the created oral vaccination to be placed in food baits in areas known to have an anthrax problem, such as Edwards Plateau in Central Texas. Edwards Plateau, an area in West Texas that has presented with frequent anthrax outbreaks in the past, had a spike in anthrax related deaths in 2019 that took the lives of about 10,000 animals within a few months.^1,2

A challenge that researchers are facing is the complicated process of turning a vaccination that is supposed to be administered through the skin as an oral treatment. According to Jamie Benn Felix, PhD, an assistant professor at Texas A&M University-Kingsville’s Caesar Kleberg Wildlife Research Institute, the problem is that anthrax spores do not remain in the gastrointestinal tract to develop an immune response without help.

Benn Felix, through her postdoctoral research associate at Texas A&M University’s Cook Wildlife Lab, was able to create a new formula for the oral vaccine using microencapsulation. This formula works by using protective membrane to slowly release bacteria in a rate that will generate an immune response.³ This was made possible with help from another team member, Allison Rice-Ficht, PhD, who created the encapsulation technique that protects the brucellosis vaccine from the stomach’s acid.

“We’re very grateful to our funding partners at the Centers for Disease Control and Prevention, the American Association of Zoo Veterinarians, and the Second Ark Foundation of the Exotic Wildlife Association for supporting this important research,” Cook said.

“We would also like to thank Alice Blue-McLendon, DVM, a clinical associate professor in the VMBS’ Department of Veterinary Physiology and Pharmacology, for her assistance and for allowing us to include deer at the Winnie Carter Wildlife Center in our study,” he said.

References

1. Price C. Texas A&M Researchers See Success In First Tests Of Oral Anthrax Vaccine In White-Tailed Deer. Texas A&M Today. Published October 30, 2024. Accessed October 30, 2024. https://today.tamu.edu/2024/10/30/oral-anthrax-vaccine-for-deer-success/
2. ‌Blackburn JK, Goodin DG. Differentiation of springtime vegetation indices associated with summer anthrax epizootics in west Texas, USA, deer. J Wildl Dis. 2013;49(3):699-703. doi:10.7589/2012-10-253
3. Price C. Texas A&M CVMBS Researcher Developing First Oral Anthrax Vaccine For Livestock, Wildlife. Texas A&M Today. Published August 10, 2020. Accessed October 30, 2024. https://vetmed.tamu.edu/news/press-releases/texas-am-cvmbs-researcher-developing-first-oral-anthrax-vaccine-for-livestock-wildlife/?_gl=1