The role of New Zealand endemic lizards in Salmonella transmission in the takahē translocation network
The dynamics of disease in wildlife populations often involve a complex relationship between physiological, environmental and ecological variables. Defining the pattern of pathogen infection between primary hosts, sympatric species and their environments is crucial in the understanding of potential impacts a pathogen may have on its host species. Very little is known about pathogens of native, New Zealand wildlife. Understanding the role pathogens play in structuring communities is crucial in the conservation of threatened New Zealand wildlife species. Salmonella is an important pathogen of reptiles, birds and mammals, and Salmonellosis has caused significant mortality in wildlife around the world. Recently, Salmonella has been isolated from takahē from a private island in the takahē translocation network. Reptiles have been implicated as asymptomatic carriers and transmitters of Salmonella, and lizards from a private (undisclosed) island have been implicated in the transmission of Salmonella to takahē. To investigate the capacity for lizards to act as a Salmonella reservoir in the takahē translocation network, I examined the distribution, abundance and Salmonella prevalence of lizards within takahē territories on the private island and on Maud Island where takahē also reside. Additionally, I investigated the presence of Salmonella in soil and water samples from takahē territories on the private island, Maud Island and at the Burwood Bush takahē rearing facility. Lizard densities on the private island were estimated to be between 466-6020 lizards/ha, and 118-1528 lizards/ha on Maud Island. Salmonella serovars concurrent with those isolated from takahē were isolated from 2% of lizards, 25% of water and 50% of soil samples on the private island, indicating that lizards and the environment play an important role in transmission and maintenance of Salmonella to takahē. Salmonella was not isolated from lizards or environmental samples on Maud Island or at Burwood Bush, indicating prevalence too low to detect in this study or a Salmonella reservoir unique to the private island. Further investigation of Salmonella sources; serovars and seasonal patterns of Salmonella infection is needed to better inform takahē translocation actions on the private island. Additionally, further examination of Salmonella in lizards and the environment is necessary to assess the risk of Salmonella infection to takahē on Maud Island.