SUMMARY1. Ninety-seven (83.6%) of 116 reptiles, comprising 70 lizards, 40 snakes, 4 tortoises and 2 crocodiles, yielded isolations of organisms in the Salmonella and/or Arizona groups.2. The reptiles were captive or free-ranging; the former were drawn from all states of mainland Australia, while the latter were from West Australia only.3. The relative prominence ofSalmonellaserotypes containing numerically highsomatic antigens, the finding of newserotypes, of multiple infections, and of strains in subgenera II and III was remarked.4. The lack of evidence of differences in the serotypes isolated from captive or wild reptiles (except for the isolation ofS. typhimuriumin creatures closely associated with man and his domestic fauna), and the apparent absence of a specific geographical distribution of serotypes in reptiles, lent support to the con clusion that reptiles provide a natural reservoir forSalmonellaand Arizona strains in Australia. The possible spill-over to man, his domestic animals and his food stuffs is discussed.It is a pleasure to record our indebtedness to Dr Joan Taylor for her continuous interest and support in providing confirmation and identification of manySalmonellaserotypes; to Dr W. H. Ewing and later Dr R. Rhode for serotyping the Arizona strains; to Dr G. M. Storr, Curator of Reptiles in the Museum of Western Australia, for identifying the reptiles and to Dr W. S. Davidson, Commissioner of Public Health, Western Australia, for permission to publish.

SUMMARYStrontium chloride B medium and E.E. broth have been found effective in the recovery of Edwardsiella, Salmonella and Arizona species from the cloacal contents of tiger snakes (Notechis scutatus). Strontium chloride B medium was superior to E.E. broth.At least one bacterial species was detected in each of the 60 reptiles examined, and all three organisms were recovered from each of 29 snakes on a single examination.Strontium chloride M, strontium selenite and Rappaport enrichment media and bismuth sulphite agar, although satisfactory for the isolation of Salmonella and Arizona species, were found unsuitable for Edwardsiella tarda.

SUMMARYSalmonella javiana, a serotype rarely isolated in Australia, has been recovered from the faeces of a 14-month-old infant with symptoms of enteritis.The child had been closely associated with a marsupial species, the quokka, during a vacation on Rottnest Island in Western Australia, and S. javiana was isolated from faecal pellets from adult quokkas, and also from a snake collected on the island.Sampling revealed a high incidence of Salmonella infection in the quokkas. In all, 62 out of 87 animals (71 %) were found to be infected, and 17 Salmonella and 3 Arizona serotypes were identified from 100 isolations comprising 92 salmonellas and 8 arizonas. Multiple infections were frequently detected and up to four serotypes were recovered from individual animals. S. javiana was isolated from four quokkas.A close parallel was observed between the serotypes isolated from quokkas and sea-gulls on the island, and abattoir effluents, lake waters, bird droppings and reptiles sampled on the adjacent mainland.The epidemiological significance of Salmonella and Arizona infections in the quokka population and their possible association with the seasonal decline in condition and numbers of animals on Rottnest Island is discussed.

No abstract

An unusual abundance of Salmonella infections was studied in an island population of a wild marsupial, the quokka (Setonix brachyurus), which experiences starvation in summer associated with significant mortality. The frequency of infections was found to vary seasonally over most parts of the island, with high infection rates (70 to 100%) in summer and low infection rates (0 to 30%) in winter. In some samples, there was an average of as many as two isolations per animal, and up to five isolations were made from a single animal. By the end of summer, virtually all animals excreted Salmonella spp., with a median rate of excretion of approximately 3,000 Salmonella organisms per g of feces. The seasonal changes occurred over intervals of only weeks. The infections are believed to be associated with disruption of the digestive physiology of the animals caused by the poor quality of feed available in summer. This conclusion was supported by a quantitative study of the infections and by a field manipulation experiment which delayed the initiation of the infections as long as a food supplement was available. The proliferation of Salmonella spp. is discussed in terms of the ecology of the quokka and of the use of Salmonella spp. as indicators of environmental stress acting on the animals.