Controlling infectious disease between wildlife and livestock on shared rangeland

Birds and cattle often comingle and the potential of disease transmission is inevitable. Texas A&M AgriLife scientist Sapna Dass, Ph.D., is targeting that transaction with her latest research. 

Sapna Chitlapilly Dass, Ph.D., assistant professor in microbial ecology and microbiome interactions, Department of Animal Science, is studying the ongoing threat of emerging pathogens that can necessitate prompt deployment of medical countermeasures for life-saving interventions.

And Dass, a Texas A&M AgriLife researcher in the College of Agriculture and Life Sciences, wants to nip it in the bud, so to speak.

Rangeland level

She wants to address the potential of disease transmission at the rangeland level rather than waiting until it reaches the SARS-CoV-2 virus level in the human population. She worked extensively on solving problems with COVID-19 in the supply chain.

“Dairy cattle are not a known host for avian influenza, so that was quite a shocker when it jumped species,” she said. “Disease transmission is inevitable, and we will see more with unusual hosts getting this disease. So, we should take care of what we can fix before it can become human-to-human transmission.”

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Dass is leading a research initiative dedicated to identifying pathogens, monitoring transmission pathways, and implementing rapid responses to address the potential danger posed by unidentified pathogens that could lead to severe epidemics.

The project, “A systems approach to understanding wildlife-farm animal-environmental drivers of zoonotic disease transmission in the food supply chain,” is funded by a $3.03 million U.S. Department of Agriculture Animal and Plant Health Inspection Service grant.

History tells us

Out of the 400 recorded instances of emerging infectious diseases since 1940, Dass said bacterial pathogens constitute 54%, viral or prion pathogens 25%, protozoa 11%, fungi 6%, and parasitic worms 3%.

Despite their lower frequency, RNA viruses, such as those responsible for HIV, influenza H1N1 and H5N1, SARS-CoV-2, Lassa virus, Ebola virus and MERS-CoV have caused the most devastating recent emergence events.

“Human intersection with ecosystems, which is driven by urban expansion, along with the proximity of agricultural lands to wildlife habitats and the extending range of wildlife reservoirs collectively amplify the occurrence of zoonotic diseases,” Dass said.

This research project employs SARS-CoV-2 as a model virus to study spillover events from white-tailed deer to livestock, examine mechanisms of virus persistence in the environment, and assess their potential impact on human health.

“We want to determine what we can do before a disease reaches the point of vaccinating humans; fix the root cause,” she said. “The root cause is the wildlife and livestock intermingling. If we can take care of that, we can prevent overwhelming the healthcare system, which took a beating during the SARS-CoV-2 pandemic.”

The project

The project allows both wildlife and livestock to be put in a controlled environment to see whether the transmission happens. It is a lengthy procedure, but the USDA’s National Animal Disease Center in Ames, Iowa, has done a phenomenal job of cohabiting the animals so “we can get real-world disease transmission results,” Dass said.

“With our systems approach, we can look at environmental maintenance of the virus, using our Biosafety Safety Level 3 facility at the Global Health Research Complex,” she said. “For example, what occurs in a water trough or elsewhere when both livestock and wildlife drink water from the same source on the rangeland?”

Dass said this complex research requires collaboration between scientists from different specialties working together — people in animal disease, veterinary biosciences, wildlife and genomics.

The team working with Dass includes:

• Tammi Johnson, Ph.D., AgriLife Research wildlife disease ecologist and associate professor in the Department of Rangeland, Wildlife and Fisheries Management, Uvalde, concentrating on wildlife disease ecology.
• Martial Ndeffo, Ph.D., assistant professor, Texas A&M Veterinary Integrative Biosciences, School of Veterinary Medicine and Biomedical Sciences, Bryan-College Station, who specializes in infectious disease transdisciplinary modeling.
• Paola Boggiatto, Ph.D., DVM, National Animal Disease Center, Ames, Iowa, who works on mixed species disease transmission between whitetail deer and livestock at the animal biosafety level 3 lab.
• Jason McDermott, Ph.D., Pacific Northwest National Laboratory, Richland, Washington, who specializes in systems biology and multiomics modeling.

“Infectious disease transmission is expected to happen,” Dass said. “But we’ll find out if and how it can be controlled by limiting exposure.”