As summer approaches, many of us relish the great outdoors. But lurking in those grassy fields is a rising concern: ticks. This tick season is starting earlier and lasting longer, with these tiny creatures invading regions they previously left untouched, bringing with them the risk of tick-borne viruses.

The Powassan Virus: A Growing Concern

In North America, one tick-borne virus that's gaining attention is the Powassan virus (POWV). Known for causing serious illnesses like encephalitis, seizures, paralysis, and even coma, cases of POWV infections have surged in recent years, yet no effective treatments exist, warns Joyce Jose, an associate professor of biochemistry and molecular biology at Penn State.

"Understanding this virus's structure is crucial for developing prevention and treatment strategies," states Joyce, who, alongside a dedicated team from Penn State, the University of Minnesota, and the US Department of Agriculture, has unveiled a groundbreaking 3D model of the POWV.

Revolutionary Research Published

Their eye-opening discoveries were recently featured in the journal 'Science Advances.' POWV belongs to the Flaviviridae family, infamous for notorious viruses like West Nile, dengue, and yellow fever, transmitted by ticks—nature's stealthy vectors.

A New Approach to Study a Dangerous Virus

Due to the severe health risks posed by POWV, researching it in its natural form is quite difficult. Researchers commonly inactivate the virus using chemicals or ultraviolet light; however, these methods often compromise the virus's integrity, hindering high-resolution analysis.

To tackle this challenge, the team opted for a clever workaround: using a weakened yellow fever vaccine virus as a substitute. By replacing two of its protein genes with those from POWV, they managed to create a hybrid that retained key structural information.

Cryo-EM: A Game-Changer in Virus Imaging

The researchers employed Cryo-Electron Microscopy (cryo-EM) at Penn State’s state-of-the-art facility, a cutting-edge technique that captures the 3D structure of proteins and viruses with near atomic precision. "When I began my career, viruses appeared as blobs due to low resolution," Joyce reflects. "Now, we can discern every molecule, understanding how they fit together and identifying which are exposed and accessible."

Unlocking the Secrets of Viral Transmission

Grasping the structure of POWV is essential for shedding light on its transmission dynamics, an area still poorly understood. Intriguingly, the team discovered that the type of host for virus transmission is dictated not by the structural proteins but by the nonstructural ones.

"Our research revealed that viruses transmitted by mosquitoes cannot be transmitted by ticks, and the reverse is also true, though the mechanisms behind this barrier remain a mystery," Joyce explains.

Implications for Future Treatments and Vaccines

Understanding the virus's surface—specifically the proteins it presents—is the first step toward unraveling virus-host and virus-vector interactions. This knowledge could pave the way for effective vaccines and therapies, as these interactions are often the targets of medical interventions.

Looking ahead, the team plans to further explore the complexities influencing how viruses are transmitted, potentially unlocking new avenues to combat these stealthy threats.