There is often a high prevalence of Salmonella carriage and shedding in captive reptiles. It has been suggested that this may be due to contact with humans and domestic animal species, or the stress of captivity. Little is known about the ecology of Salmonella in truly wild reptiles.In Australia, the rates of human salmonellosis are highest in Northern Australia, with consistently high rates observed in the Kimberley region of Western Australia. The aim of this study was to investigate the prevalence and serotypes of Salmonella in wild reptiles in the Kimberley.
In May 2011, 130 wild reptiles belonging to 41 different species were caught in the Kimberley region of Western Australia. Cloacal swabs were taken for the isolation of Salmonella. Isolates were obtained via selective enrichment, and identified via biochemical tests and serotyping.
Forty percent of reptiles sampled were positive for Salmonella. Nineteen different Salmonella enterica serotypes were identified, belonging to subspecies I, II, IIIb and IV. The most common serotype was Salmonella Rubislaw (prevalence = 10.8%).
This study showed a high prevalence of Salmonella in wild reptiles in the Kimberley. These reptiles have had minimal contact with humans and domestic species, suggesting that they are natural carriers of Salmonella. The main serotypes identified differed from the most common isolates in cases of human disease, but many have known pathogenicity in humans. Three of the top ten human Salmonella serotypes identified in 2011 in Western Australia – Paratyphi B biovar Java, Chester and Muenchen – were isolated from reptiles in this study. The high prevalence of Salmonella in these wild reptiles and the Salmonella serotypes reptiles and humans have in common, suggests that reptiles are likely to be significant contributors to the natural ecology of Salmonella and a significant reservoir for the organism.