Combatting an emerging disease threatening endangered Christmas Island reptiles

Project Summary Project 2.3.5

Listers Gecko. Photo: Kirsty Faulkner

Research in Brief Why is the research Small numbers of geckos within the Christmas Island captive breeding The blue-tailed skink and Lister’s needed? colony have become infected; gecko are unique to Christmas Although once abundant and however, the swift implementation of Island. They are critically widespread on Christmas Island, the quarantine and biosecurity protocols endangered, currently extinct Lister’s gecko (Lepidodactylus listeri) minimised disease spread, and the in the wild, and persist only within and blue tailed skink (Cryptoblepharus captive colony is currently disease-free. a captive breeding program. egeriae) are now extinct in the The disease has been documented Recently, a new bacterial disease wild, and only persist within captive in free-ranging invasive Asian house which causes facial deformity breeding programs on Christmas geckos across Christmas Island. Island and at Taronga Zoo in Sydney. and death has been identified The cause of the disease has been Invasive species, especially the in the two species. It poses identified as a newly described Common Asian wolf snake, are a major threat to the survival species of Enterococcus bacterium. considered the main cause of these already threatened Without research and management, of extinction in the wild. populations. This research will this poorly understood disease may build on preliminary findings to In 2014, a new disease was identified prove catastrophic for the small and develop a critical understanding in reptiles in the captive breeding vulnerable remaining populations of of the disease, how it interacts program on Christmas Island. Animals endangered reptiles. Little is known with the reptiles and their affected by the disease initially about the mechanisms of disease environments, and if and how develop swelling around the head or the likelihood of this bacteria it can be managed. and eyes followed by destruction of spreading to other species. To our Infected gecko. bones and internal organs. Reptiles knowledge, the disease has not spread Photo: Justin Welbergen succumb to death as early as a few beyond Christmas Island; however the weeks to six months from the initial susceptibility of local reptiles suggests display of disease. In all cases, with the bacteria may pose a threat to a the exception of a single blue-tailed variety of species if it ever spread to skink, infection results in death. mainland Australia or elsewhere. Image: Electron microscopy image of bacterium. Photo: Mukesh Srivastava

How will the research What research activities The Australian Pacific Science Foundation, Taronga Conservation help? are being undertaken? Science Initiative, Holsworth, and The research will fill knowledge gaps The research will build upon Perpetual are also supporting this and identify management strategies preliminary findings established by research project. for the newly identifiedEnterococcus studies undertaken in late 2015, sp. which is fatally affecting native and will include: Where is the research Christmas Island reptiles. This is 1. Screening genetic sequence happening? essential to ensuring the health of data of the bacterium to identify The laboratory work associated with captive blue-tailed skink and Lister’s genes that code for resistance the project is being undertaken at gecko populations, and successful to antibacterial drugs; traits that The University of Sydney, with the reintroduction into the wild. allow the bacterium to maintain field work component carried out The project will investigate the virulence; and the metabolic on Christmas Island. disease from a number of aspects requirements necessary for to identify: growth and replication of When is the research the bacterium. • How the disease is transmitted happening? 2. Microscopically examining • How the bacterium is able to avoid The project will run from early diseased tissues from infected the immune system and cause 2017 to 2020. such extensive disease reptiles to determine how they replace healthy tissue, their • The source of the bacterium and bacterial load and bacterial how it persists in the environment shedding. • Treatment options for infected reptiles 3. Sampling native and invasive reptiles, reptile prey/food • Prevention protocols for healthy and areas in the environment; reptiles then analysing samples to The research will develop evidence determine the potential source based guidelines for Christmas Island of this bacterium and reservoirs National Park staff to treat infected of infection. animals, prevent infection in captive 4. Use genetic sequence data animals, and limit/mitigate the and antibiotic sensitivity trials spread of infection within wild and to determine which treatments captive reptile populations and the are most effective. environment on Christmas Island. This will be essential to the long-term Who is involved? conservation of both species and for Researchers from the University of any future translocation programs. Sydney are working collaboratively

The project will also help identify with Parks Australia, Christmas Island Jessica Agius in the lab. Photo: Charley Pollard the potential risk of spread beyond National Park staff, the Australian Christmas Island and arm quarantine Registry of Wildlife Health, Taronga agencies with strategies to reduce Conservation Society Australia, the Further Information the risk of spread and to identify, National Environmental Science For more information please quarantine and treat any outbreaks. Program, and the Australian Museum. contact University of Sydney Ph.D. candidate: Jessica Agius [email protected]

This project is supported through funding from the Australian Government’s National Environmental Science Programme.