Oral Presentation 64th International Conference of the Wildlife Disease Association 2015

Systemic coccidiosis in green turtles (Chelonia mydas) in Australia: An emerging infectious disease (#84)

Silvia Ban de Gouvea Pedroso 1 , David N Phalen 1 , Duan March 2 , David Blyde 3 , Anita Gordon 4 , Phoebe Chapman 5 , Paul Mills 5 , Amber Gillett 6 , Hannah Lloyd 7 , Geoff Ross 7 , Jane Hall 8 , Jennifer Scott 9 , Ellen Ariel 9 , Karrie Rose 8
  1. Faculty of Veterinary Science, University of Sydney, Sydney, New South Wales, Australia
  2. Dolphin Marine Magic, Coffs Harbour, New South Wales, Australia
  3. Village Roadshow Theme Parks, Gold Coast, Queensland, Australia
  4. Biosecurity Sciences Laboratory, Department of Agriculture and Fisheries, Cooper Plains, Queensland, Australia
  5. School of Veterinary Science, University of Queensland, Brisbane, Queensland, Australia
  6. Australia Zoo Wildlife Hospital, Beerwah, Queensland, Australia
  7. Office of Environment and Heritage, NSW National Parks and Wildlife Service, Sydney, New South Wales, Australia
  8. Australian Registry of Wildlife Health, Taronga Conservation Society Australia, Taronga Zoo, Sydney, New South Wales, Australia
  9. College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia

Outbreaks of infectious disease are increasingly recognised in marine turtles and, in some cases, may be indicative of a broader underlying ecosystem disruption. The coccidial parasite Caryospora cheloniae was first described in captive green turtle (Chelonia mydas) hatchlings experiencing severe inflammatory disease of the hindgut in the Cayman Islands in 1973.1 The first epizootic of coccidiosis in wild green turtles occurred in Moreton Bay, Australia in 1991. On this occasion, turtles had lesions throughout the intestine, sparing only the duodenum. Many also had extra-intestinal lesions of which the brain was a common target organ.  Based on the morphology of the oocysts which was similar but not identical to those described previously, this organism was thought to be Caryospora cheloniae.2 Subsequently, epizootics of these Caryospora-like organisms in green turtles have occurred repeatedly along the east coast of Australia. We have collected all of the available temporal, spatial, clinical and necropsy data on known outbreaks occurring between 1991 and 2014. Using this data we will provide the most comprehensive picture to date of the number and timing of disease outbreaks in green turtles caused by this Caryospora-like organism, the age class of affected turtles, clinical signs, and distribution of lesions. We will also show whether or not these epizootics are linked with specific climate conditions.  The data generated by this study will help to better understand the epizootiology of this disease and hopefully provide a means to mitigate its impact. 

  1. Leibovitz L, Rebell G, Boucher GC. 1978. Caryospora cheloniae sp. N.: A coccidial pathogen of mariculture-reared green sea turtles (Chelonia mydas mydas). J Wildlife Dis 14: 269-275
  2. Gordon AN, Kelly WR, Lester, RJG. 1993. Epizootic mortality of free-living green turtles, Chelonia mydas, due to coccidiosis. J Wildlife Dis 29:490-494.