By Blake Jackson
Each foaling season, breeding farms may face a familiar and urgent scenario: a foal that appeared healthy hours earlier suddenly becomes weak, stops nursing, and develops watery diarrhea.
One of the leading causes is equine rotavirus A (ERVA), a highly contagious virus that primarily affects foals under six months of age and can escalate rapidly without intervention. Addressing this challenge is a focus of ongoing research at the Martin-Gatton College of Agriculture, Food and Environment.
Feng Li, a virologist at the University of Kentucky’s Maxwell H. Gluck Equine Research Center, explains that ERVA continues to challenge prevention efforts because it constantly evolves.
“It’s an old virus, but it keeps changing,” Li said. “Those changes can add up in ways that matter on farms: Vaccines and mare antibodies can lower risk, yet infections still break through in some settings, especially as foals age and protection fades.”
Li is developing what has been largely absent from equine rotavirus research: a genetic toolbox that allows scientists to study ERVA in controlled laboratory conditions and link genetic changes to real-world disease outcomes. Rotaviruses contain 11 separate genetic segments, enabling frequent variation and the emergence of multiple strains.
“You can have a vaccine and still see breakthrough infection,” Li said. “The question is why, and which viral changes are linked to that slip.”
The research includes sequencing ERVA from infected foals to identify circulating strains, creating standardized reference viruses for comparison, and testing how effectively antibodies neutralize different variants. This approach connects genetic changes with immune protection.
“Right now, we don’t have good lab tools to study how rotavirus A mutates and how those mutations affect immunity. That’s what we’re building here at the University of Kentucky,” Li said.
“This toolbox will let us isolate different rotavirus A strains, read their full genome sequences and see how each mutation affects virus behavior. We’re creating a system where we can introduce changes we see from naturally occurring field isolates into the virus one at a time and ask: Does this make it escape antibodies or vaccine-mediated protection?”
Photo Credit: gettyimages-patrick-jennings
Categories: Kentucky, Education, Livestock