On Aug. 12, 2025, Powassan virus (POWV), a type of flavivirus closely related to the Zika and Dengue viruses, is an emerging tick-borne virus spreading across North America. In humans, it can cause symptoms like brain swelling, paralysis, seizures, and coma. Its mortality rate is estimated to range from about 12.5% to 17.9%, and survivors often experience long-term neurological symptoms. To date, there are no vaccines or antiviral treatments for POWV.

New research published by Professor and CryoEM Director Susan Hafenstein, PhD, and Graduate Assistant Sayan Das at The Hormel Institute, University of Minnesota, in the leading scientific journal Science Advances could take us closer to developing therapeutics.

Using cryogenic-sample electron microscopy (cryoEM) technology, one of the world’s most powerful forms of microscopy, The Hormel Institute scientists generated an atomic-level, high-resolution 3D structure of POWV. That allowed them to observe sugar molecules on the virus’s shell that play a role in how the virus attaches to enter the human host. They also discovered three secret lipid pockets within the virus that are crucial to its stability—and “one of which might just prove to be the virus’s Achilles heel,” Das explained.

“The project is a beautiful intersection of curiosity, collaboration, and public health,” Das said. “Our study not only provides a structure of the virus, but also helps establish a suitable platform to study this virus safely, design safe and effective vaccines against it, and develop antivirals to treat infections. To me, this project is a perfect example of how science can be used to solve real-world problems.”

This project was done in collaboration with the Department of Biochemistry and Molecular Biology and The Huck Institutes of the Life Sciences at The Pennsylvania State University, as well as the U.S. Department of Agriculture.