Researchers are focusing on the immune systems of Indian River Lagoon green sea turtles as they search for why nearly half are covered with tumors.
A turtle herpesvirus is believed to be behind the tumors that can grow inside and outside of the sea turtles' bodies, obstructing internal organs and affecting eyesight and mobility.
But Anna Savage of the University of Central Florida says not every sea turtle with the virus develops the tumors, which led researchers to focus on their immune systems.
"The idea is that if you've got the right flavor of these genes you're going to be able to effectively respond to the viral infection and you're not going to suffer from this disease that a turtle that doesn't have that right flavor of the genes is going to not be able to fight off and is going to get the disease."
Researchers also are considering environmental factors. Green sea turtles are endangered. The ailing Indian River Lagoon is the focus of a regional restoration effort.