Scientists Seek to Understand Deadly Virus Targeting Florida’s Freshwater Turtles

New research hints at how turtle fraservirus 1 is transmitted and how to limit its spread.

By the editorial staff of Park Science magazine

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About this article

This article was originally published in the "Research Roundup" section of Park Science magazine, Volume 39, Number 2, Summer 2025 (August 29, 2025).

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Florida softshell turtle at Everglades National Park. This species is one of four freshwater turtle species that scientists examined in new research into turtle fraservirus 1.

Image credit: NPS / R. Cammauf

Turtles look tough, and in many ways, they are. They’ve been around since dinosaurs roamed the earth. But now, turtles are some of the most threatened animals out there, with more than half at some risk of extinction. Exploitation and habitat loss are the main culprits, but diseases are a growing concern too. In 2018, Florida scientists identified a deadly new virus afflicting freshwater turtles. It’s called turtle fraservirus 1, or TFV1, and almost everything about it, like how it’s transmitted, remains uncertain.

To learn more, the Florida Fish and Wildlife Conservation Commission started soliciting reports of dead or sick turtles and collecting carcasses for examination. A team of researchers analyzed the reports and necropsy results collected from March 2018 through September 2021 to find patterns and guide cost-efficient turtle disease investigations. They published their findings in PLoS ONE in April 2025. The study included data from 117 turtles of four different species.

More than half of the turtles tested positive for TFV1. Florida softshell turtles that tested positive often had an abnormal layer of yellowish-green material (termed “plaques”) on the tissue lining the inside of the mouth and rear orifice. Dead or dying turtles found in clusters were also more likely to test positive, suggesting the virus may be easily transmissible through water. This finding also indicates that aquatic biosecurity measures could help limit the spread of TFV1.

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Shender and others. 2025. Epidemiological factors associated with Turtle fraservirus 1 (TFV1) in freshwater turtles in Florida, USA. PLoS ONE 20(4): e0320097.