Sea Turtle Diseases Active
Sea turtles are one of the oldest groups of reptiles and are found worldwide. There are seven species of sea turtles in the world, and Hawaii has two of them, the hawksbill and the far more numerous green turtle. Threats to turtles include by-catch from fisheries activity, over harvesting of eggs on nesting beaches, and disease. Of the latter, the most significant disease of sea turtles is called fibropapillomatosis (FP).
Research on Fibropapillomatosis (FP)
Since 1995, the Honolulu Field Station and National Marine Fisheries Marine Turtle Biology and Assessment Program have had an ongoing collaboration to elucidate the cause and epizootiology of fibropapillomatosis (FP). FP causes unsightly external and internal tumors in sea turtles. It affects mainly green and loggerheads and is found in almost all the tropical marine ecosystems where these species reside. FP has also been documented in other species of sea turtles, but much more infrequently. FP was first described in green turtles from Florida in the early 1920s. In Hawaii, the first record of the disease occurred somewhere about the early to mid-1950s. FP affects mainly immature turtles, and in Hawaii, the percentage of individuals affected can range from 20 to 40% depending on the location. In addition to causing tumors on the skin, eyes, and mouth, about 20-30% of sea turtles with the disease also have tumors in internal organs such as the lungs, kidneys, and heart.
What causes FP?
FP was deemed not much more than a curiosity until the 1980s and 90s when serious research began on the disease. Microscopic examination of tumors by researchers as the University of Florida, Gainesville, revealed particles suggestive of a herpes virus. Since herpes viruses are known to cause tumors in animals and humans, this agent as a potential cause of FP was certainly plausible. However, many other things can cause tumors in animals. Investigators in Florida then reproduced the disease in captive green turtles by injecting tumor homogenates that had been filtered to eliminate all but the smallest particles (viruses). In doing so, they were able to reproduce tumors similar to those seen in the wild. This was very compelling evidence that whatever caused the disease, it was either something very small (maybe a virus or protein) but almost certainly not something like a bacterium or parasite that would have been eliminated in the filtration process. Subsequent molecular biology studies have consistently shown the presence of a herpesvirus in tumors.
Effects of FP on turtles
Although FP is a major threat of stranding of sea turtles in Hawaii, the disease is waning in Hawaii for unknown reasons. In contrast, its presence is increasing in Florida, and it has recently appeared in Texas. About 30% of turtles recover from the disease, so it has detrimental effects on affected animals. Turtles with severe FP become immunosuppressed and get secondary bacterial infections. Furthermore, many stranded turtles have concomitant infections with worms that live in blood vessels and cause inflammation of internal organs. Hawaii is also unique in that turtles here get tumors in the glottis (opening to the trachea). This prevents closure of the glottis allowing seawater and food to get into the lungs. Not surprisingly, many turtles that strand with glottal tumors also have infections and inflammation in the lungs. A system to score the severity of FP in Hawaiian green turtles shows that animals with moderate to severe disease have a lower likelihood of being observed again in the wild. All this implies that FP is more than a mere cosmetic disease and warrants further investigation.
Where to go from here?
In order to have any hope of managing this disease, several critical pieces of information are needed. How is the virus transmitted? Why does FP show up more often in what appear to be "degraded" habitats? Does the herpes virus cause the tumors? The presence of a highly visible disease in a large animal like the turtle suggests something is awry with the ecosystem. Understanding why this is so may add a piece to the puzzle of sustainable management of marine ecosystems.
Resources
Sea Turtle Necropsy Manual
- English language edition
- Spanish language edition
- Italian language edition
- Japanese language edition
- Chinese (simplified) edition
- Chinese (traditional) edition
- French language edition
- Portuguese language edition
- Arabic language edition
- Korean language edition
- Persian language edition available by request to asknwhc@usgs.gov
Below are multimedia items associated with this topic.
Below are publications associated with this topic.
Green turtles (Chelonia mydas) have novel asymmetrical antibodies
Topsy-turvy: Turning the counter-current heat exchange of leatherback turtles upside down
Causes of mortality in green turtles from Hawaii and the insular Pacific exclusive of fibropapillomatosis
Health condition of juvenile Chelonia mydas related to fibropapillomatosis in southeast Brazil
Dynamics of virus shedding and in situ confirmation of chelonid herpesvirus 5 in Hawaiian green turtles with Fibropapillomatosis
The story of invasive algae, arginine, and turtle tumors does not make sense
Pink spot, white spot: the pineal skylight of the leatherback turtle (Dermochelys coriacea Vandelli 1761) skull and its possible role in the phenology of feeding migrations
Investigating the potential role of persistent organic pollutants in Hawaiian green sea turtle fibropapillomatosis
Unique characteristics of the trachea of the juvenile leatherback turtle facilitate feeding, diving and endothermy
Immunological evaluation of captive green sea turtle (Chelonia mydas) with ulcerative dermatitis
Tumors in sea turtles: The insidious menace of fibropapillomatosis
A simple humane method to euthanize a sea turtle
Below are news stories associated with this topic.
- Overview
Sea turtles are one of the oldest groups of reptiles and are found worldwide. There are seven species of sea turtles in the world, and Hawaii has two of them, the hawksbill and the far more numerous green turtle. Threats to turtles include by-catch from fisheries activity, over harvesting of eggs on nesting beaches, and disease. Of the latter, the most significant disease of sea turtles is called fibropapillomatosis (FP).
Research on Fibropapillomatosis (FP)
Since 1995, the Honolulu Field Station and National Marine Fisheries Marine Turtle Biology and Assessment Program have had an ongoing collaboration to elucidate the cause and epizootiology of fibropapillomatosis (FP). FP causes unsightly external and internal tumors in sea turtles. It affects mainly green and loggerheads and is found in almost all the tropical marine ecosystems where these species reside. FP has also been documented in other species of sea turtles, but much more infrequently. FP was first described in green turtles from Florida in the early 1920s. In Hawaii, the first record of the disease occurred somewhere about the early to mid-1950s. FP affects mainly immature turtles, and in Hawaii, the percentage of individuals affected can range from 20 to 40% depending on the location. In addition to causing tumors on the skin, eyes, and mouth, about 20-30% of sea turtles with the disease also have tumors in internal organs such as the lungs, kidneys, and heart.
What causes FP?
FP was deemed not much more than a curiosity until the 1980s and 90s when serious research began on the disease. Microscopic examination of tumors by researchers as the University of Florida, Gainesville, revealed particles suggestive of a herpes virus. Since herpes viruses are known to cause tumors in animals and humans, this agent as a potential cause of FP was certainly plausible. However, many other things can cause tumors in animals. Investigators in Florida then reproduced the disease in captive green turtles by injecting tumor homogenates that had been filtered to eliminate all but the smallest particles (viruses). In doing so, they were able to reproduce tumors similar to those seen in the wild. This was very compelling evidence that whatever caused the disease, it was either something very small (maybe a virus or protein) but almost certainly not something like a bacterium or parasite that would have been eliminated in the filtration process. Subsequent molecular biology studies have consistently shown the presence of a herpesvirus in tumors.
Effects of FP on turtles
Although FP is a major threat of stranding of sea turtles in Hawaii, the disease is waning in Hawaii for unknown reasons. In contrast, its presence is increasing in Florida, and it has recently appeared in Texas. About 30% of turtles recover from the disease, so it has detrimental effects on affected animals. Turtles with severe FP become immunosuppressed and get secondary bacterial infections. Furthermore, many stranded turtles have concomitant infections with worms that live in blood vessels and cause inflammation of internal organs. Hawaii is also unique in that turtles here get tumors in the glottis (opening to the trachea). This prevents closure of the glottis allowing seawater and food to get into the lungs. Not surprisingly, many turtles that strand with glottal tumors also have infections and inflammation in the lungs. A system to score the severity of FP in Hawaiian green turtles shows that animals with moderate to severe disease have a lower likelihood of being observed again in the wild. All this implies that FP is more than a mere cosmetic disease and warrants further investigation.
Where to go from here?
In order to have any hope of managing this disease, several critical pieces of information are needed. How is the virus transmitted? Why does FP show up more often in what appear to be "degraded" habitats? Does the herpes virus cause the tumors? The presence of a highly visible disease in a large animal like the turtle suggests something is awry with the ecosystem. Understanding why this is so may add a piece to the puzzle of sustainable management of marine ecosystems.
Resources
Sea Turtle Necropsy Manual
- English language edition
- Spanish language edition
- Italian language edition
- Japanese language edition
- Chinese (simplified) edition
- Chinese (traditional) edition
- French language edition
- Portuguese language edition
- Arabic language edition
- Korean language edition
- Persian language edition available by request to asknwhc@usgs.gov
- Multimedia
Below are multimedia items associated with this topic.
- Publications
Below are publications associated with this topic.
Filter Total Items: 53Green turtles (Chelonia mydas) have novel asymmetrical antibodies
Igs in vertebrates comprise equally sized H and L chains, with exceptions such as H chain–only Abs in camels or natural Ag receptors in sharks. In Reptilia, Igs are known as IgYs. Using immunoassays with isotype-specific mAbs, in this study we show that green turtles (Chelonia mydas) have a 5.7S 120-kDa IgY comprising two equally sized H/L chains with truncated Fc and a 7S 200-kDa IgY comprised ofAuthorsThierry M. Work, Julie Dagenais, Renee Breeden, Anette Schneemann, Joyce Sung, Brian Hew, George H. Balazs, John M. BeresteckyTopsy-turvy: Turning the counter-current heat exchange of leatherback turtles upside down
Counter-current heat exchangers associated with appendages of endotherms feature bundles of closely applied arteriovenous vessels. The accepted paradigm is that heat from warm arterial blood travelling into the appendage crosses into cool venous blood returning to the body. High core temperature is maintained, but the appendage functions at low temperature. Leatherback turtles have elevated core tAuthorsJohn Davenport, T. Todd Jones, Thierry M. Work, George H. BalazsCauses of mortality in green turtles from Hawaii and the insular Pacific exclusive of fibropapillomatosis
Fibropapillomatosis (FP) comprises a majority of green turtle stranding in Hawaii; however, green turtles in the Pacific are also susceptible to non-FP related causes of death. We present here necropsy findings from 230 free-ranging green turtles originating from Hawaii, the Mariana archipelago, Palmyra Atoll, American Samoa, and Johnston Atoll that died from non-FP related causes. Most turtles diAuthorsThierry M. Work, George H. Balazs, Tammy M. Summers, Jessy R. Hapdei, Alden P. TagarinoHealth condition of juvenile Chelonia mydas related to fibropapillomatosis in southeast Brazil
Packed cell volume (PCV), plasma biochemistry, visual body condition (BC), and calculated body condition index (BCI) were evaluated in 170 wild juvenile green sea turtles Chelonia mydas from an aggregation in the effluent canal of a steel mill in Brazil. Occurrence of cutaneous fibropapillomatosis (FP) was observed in 44.1% of the animals examined. BCI alone did not differ significantly between heAuthorsMarcello Renan de Deus Santos, Agnaldo Silva Martins, Cecília Baptistotte, Thierry M. WorkDynamics of virus shedding and in situ confirmation of chelonid herpesvirus 5 in Hawaiian green turtles with Fibropapillomatosis
Cancers in humans and animals can be caused by viruses, but virus-induced tumors are considered to be poor sites for replication of intact virions (lytic replication). Fibropapillomatosis (FP) is a neoplastic disease associated with a herpesvirus, chelonid herpesvirus 5 (ChHV5), that affects green turtles globally. ChHV5 probably replicates in epidermal cells of tumors, because epidermal intranuclAuthorsThierry M. Work, Julie Dagenais, George H. Balazs, Nelli Schettle, Mathias AckermannThe story of invasive algae, arginine, and turtle tumors does not make sense
We are presenting a rebuttal letter to the following article that appeared recently on PeerJ: Van Houtan KS, Smith CM, Dailer ML, and Kawachi M. 2014. Eutrophication and the dietary promotion of sea turtle tumors. PeerJ 2:e602. This article is available at the following URL: https://peerj.com/articles/602/. We argue that the article lacks an inferential framework to answer the complex question regAuthorsThierry M. Work, Mathias Ackermann, James W. Casey, Milani Chaloupka, Lawrence Herbst, Jennifer M. Lynch, Brian A. StacyPink spot, white spot: the pineal skylight of the leatherback turtle (Dermochelys coriacea Vandelli 1761) skull and its possible role in the phenology of feeding migrations
Leatherback turtles, Dermochelys coriacea, which have an irregular pink area on the crown of the head known as the pineal or ‘pink spot’, forage upon jellyfish in cool temperate waters along the western and eastern margins of the North Atlantic during the summer. Our study showed that the skeletal structures underlying the pink spot in juvenile and adult turtles are compatible with the idea of a pAuthorsJohn Davenport, T. Todd Jones, Thierry M. Work, George H. BalazsInvestigating the potential role of persistent organic pollutants in Hawaiian green sea turtle fibropapillomatosis
It has been hypothesized for decades that environmental pollutants may contribute to green sea turtle fibropapillomatosis (FP), possibly through immunosuppression leading to greater susceptibility to the herpesvirus, the putative causative agent of this tumor-forming disease. To address this question, we measured concentrations of 164 persistent organic pollutants (POPs) and halogenated phenols inAuthorsJennifer M. Keller, George H. Balazs, Frances Nilsen, Marc Rice, Thierry M. Work, Brenda A. JensenUnique characteristics of the trachea of the juvenile leatherback turtle facilitate feeding, diving and endothermy
The adult leatherback turtle Dermochelys coriacea overlaps in body size (300–500 kg) with many marine mammals, yet develops from a 50 g hatchling. Adults can dive deeper than 1200 m and have core body temperatures of 25 °C; hatchlings are near-surface dwellers. Juvenile leatherbacks have rarely been studied; here we present anatomical information for the upper respiratory tract of 3 turtles (66.7–AuthorsJohn Davenport, T. Todd Jones, Thierry M. Work, George H. BalazsImmunological evaluation of captive green sea turtle (Chelonia mydas) with ulcerative dermatitis
Ulcerative dermatitis (UD) is common in captive sea turtles and manifests as skin erosions and ulcers associated with gram-negative bacteria. This study compared clinically healthy and UD-affected captive turtles by evaluating hematology, histopathology, immunoglobulin levels, and delayed-type hypersensitivity assay. Turtles with UD had significantly lower weight, reduced delayed-type hypersensitiAuthorsFernando Alberto Muñoz, Sergio Estrada-Parra, Andrés Romero-Rojas, Erik Gonzalez-Ballesteros, Thierry M. Work, Hector Villaseñor-Gaona, Iris Estrada-GarciaTumors in sea turtles: The insidious menace of fibropapillomatosis
Early in July 2013, a colleague in New Caledonia reported the stranding of a green sea turtle on the far northwest of the island. The animal had washed up dead on a rocky beach with multiple large tumors on its neck and hind flippers. To all appearances, the turtle had fibropapillomatosis (FP), a tumor disease affecting marine turtles globally. This was the first known case of FP on the island—anAuthorsThierry M. Work, George H. BalazsA simple humane method to euthanize a sea turtle
Increased interconnectedness, communication, and demands of society require that wildlife professionals make every effort to consider animal welfare when handling animals. The challenge can be daunting, particularly when a wild animal needs to be euthanized. In some cases, biologists are in remote areas under conditions that may be less than ideal to properly and swiftly dispatch an animal, eitherAuthorsThierry M. Work, George H. Balazs - News
Below are news stories associated with this topic.