Fibropapillomatosis and Sea Turtles – Frequently Asked Questions

What is “fibropapillomatosis”?

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“Fibropapillomatosis,” commonly referred to as “FP,” is a tumor-causing disease that affects some sea turtles. It causes cauliflower-like tumors to form on the skin anywhere on the body, including the eyes and mouth. Tumors can also form in internal organs. Some sea turtles only have mild forms of the disease whereas others develop numerous or large tumors that result in debilitation and death.  The disease most commonly affects green turtles in some areas of the U.S., including locations in Florida, Hawaii, Texas, and Puerto Rico.

When was sea turtle fibropapillomatosis first observed?

The earliest reports of sea turtle FP are from Florida in the late 1800s. The disease first appears in the scientific literature in 1938. Fibropapillomatosis gained international attention beginning in the 1980s when this disease began to be commonly reported in endangered green turtle populations in the U.S. and other countries.

What sea turtle species are affected by fibropapillomatosis?

Fibropapillomatosis has been documented in all seven sea turtle species; however, green turtles are most commonly and severely affected.  Within areas where the disease is relatively common, over half of the green turtles examined may have the disease during some years.  In other sea turtle species, FP is more sporadically encountered and tends to be mild forms of the disease.

What causes sea turtle fibropapillomatosis?

Fibropapillomatosis is associated with infection by a herpesvirus called Chelonid FP-Associated Herpesvirus or Chelonid Herpesvirus 5.  However, the development of tumors is likely caused by multiple factors that we do not yet fully understand.  Studies suggest that there are links between FP and human effects on the environment, including various forms of pollution.

How do sea turtles get fibropapillomatosis?

We know that FP can be transmitted between turtles, but we do not understand how this occurs. Other marine animals may play a role. The associated herpesvirus has been found in parasitic marine leeches that attach to turtle skin and suck their blood, and on the mouths of cleaner fish. The virus also will survive in seawater and may be transmitted between turtles. Epidemiological studies suggest that FP is acquired when young sea turtles first arrive into nearshore foraging areas after spending the first years of the lives at sea.

What happens to sea turtles with fibropapillomatosis?

The fate of sea turtles with FP depends on the severity of the disease.  Some sea turtles only develop small tumors that are not life-threatening, others develop debilitating numbers of tumors, large tumors, or tumors that cause blindness or interfere with other vital functions. 

Tumors can regress (shrink and go away) in some affected turtles. We do not fully understand how frequently this occurs.  The percentage of sea turtles with FP that show signs of regression vary among studies and range from around 30% to over 60%.

How does fibropapillomatosis affect sea turtle populations?

Fortunately, some green turtle populations where FP is relatively common, including those in Florida and Hawaii, have grown despite the disease. This population growth is the result of sea turtle conservation efforts aimed at protecting sea turtles and their habitat by reducing known threats such as bycatch in fishing operations and artificial light on nesting beaches. Nonetheless, FP causes the deaths of many turtles that otherwise likely would have contributed to population growth. Also, the disease may be associated with pollution and other forms of habitat degradation. Thus, FP remains a concern for sea turtles and the health of the marine environment.

What can be done to help sea turtles with fibropapillomatosis?

Although much has been learned about sea turtle FP over the last few decades, many aspects of this disease are not yet understood. We do not currently have a strategy to reduce or eliminate FP from sea turtle populations. As we learn more about possible links with human activity, measures to alleviate the disease to at least some degree may be identified, such as through reducing sources of marine pollution.

Biologists, veterinarians, and others that work with wild sea turtles take measures to prevent unintended spread of FP during research activities or while providing care for stranded turtles with the disease. They disinfect their equipment and avoid other potential routes of disease transmission. 

For individual sea turtles with FP that are found stranded, some are treated at permitted rehabilitation facilities.  Veterinarians can surgically remove some tumors and provide treatments for related conditions.  Although such efforts provide humane care for turtles with survivable disease, these cases represent a small proportion of wild sea turtles afflicted by FP.

Can people get fibropapillomatosis from sea turtles?

No. Only sea turtles can become infected by the virus associated with this disease and only sea turtles develop this form of FP.  There are similar diseases in humans and other animals, but these are unrelated to sea turtles FP and have other causes.

What do I do if I see a stranded sea turtle?

If you see a sick, injured, stranded, or dead marine mammal or sea turtle, immediately contact your local stranding network.