WEST PALM BEACH, Fla. _ About 75% of sea turtles infected with a herpes virus that are taken to rehab facilities die _ a sobering statistic revealed in a new study that Florida Atlantic University researchers hope will guide treatment in cash-strapped turtle hospitals.
The highly contagious disease, called fibropapillomatosis, causes cauliflower-like tumors and is found mostly in green sea turtles in warm seas. It was first identified in Florida in 1938 on turtles captured in the Keys.
The Florida Fish and Wildlife Conservation Commission calls the disease "mysterious" on its website, noting that hot spots for the ailment include areas where there is heavy runoff such as the Indian River Lagoon, Lake Worth Lagoon and Florida Bay.
Annie Page-Karjian, an assistant research professor at FAU Harbor Branch Oceanographic Institute, led a team of scientists in reviewing medical records of 756 sea turtles with the disease between 2009 and 2017. Justin Perrault, director of research for the Juno Beach-based Loggerhead Marinelife Center, was a co-author of the study.
Of the records reviewed, just 193 turtles, or 25%, survived. Of the survivors, 186 were released and seven remained with a turtle facility. Results of the study were published online last month in the journal Diseases of Aquatic Organisms.
"This disease is devastating for individual turtles and even though we think it's probably not affecting their population recovery, the ones who have it can really suffer," Page-Karjian said. "To me, it means we need to get a better understanding of what is causing it and start to figure out ways to address the causes."
Green sea turtles are a federally endangered species.
Just a handful of the 22 turtle rehabilitation facilities in Florida take turtles infected with the disease because treatment can be costly and requires the turtle to be quarantined in its own tank.
Page-Karjian said several agencies, including FWC, were asking for more information on mortality rates of turtles with the disease based on the level of illness so that turtle hospitals have more information on which turtles to euthanize or treat.
While the tumors are benign, they can grow near a turtle's eyes or around their fins, making it harder for the turtle to swim and find food.
Turtles taken to rehab hospitals with the disease are ranked on a 1 to 3 scale based on the severity and number of tumors they have.
"Turtles can have upwards of 50 tumors in really bad cases," Page-Karjian said.
Depending on a rehabilitation facility's resources, turtles ranked at the highest level may be immediately euthanized.
Turtles considered treatable have their tumors removed by laser, but the FAU study showed that tumors regrew in about half of the cases.
Complicating the study was that there are multiple tumor-scoring systems used by rehab facilities with some more stringent than others. The FAU study looked at three of the scoring systems.
"A lot of these facilities have a limited staff and are working with volunteers and donations," Page Karjian said. "There was a need to understand survivorship."
