Human migration is important in the international spread of exotic Salmonella serovars in animal and human populations.

The exposure of indigenous humans and native fauna in Australia and the Wallacea zoogeographical region of Indonesia to exotic Salmonella serovars commenced during the colonial period and has accelerated with urbanization and international travel. In this study, the distribution and prevalence of exotic Salmonella serovars are mapped to assess the extent to which introduced infections are invading native wildlife in areas of high natural biodiversity under threat from expanding human activity. The major exotic Salmonella serovars, Bovismorbificans, Derby, Javiana, Newport, Panama, Saintpaul and Typhimurium, isolated from wildlife on populated coastal islands in southern temperate areas of Western Australia, were mostly absent from reptiles and native mammals in less populated tropical areas of the state. They were also not recorded on the uninhabited Mitchell Plateau or islands of the Bonaparte Archipelago, adjacent to south-eastern Indonesia. Exotic serovars were, however, isolated in wildlife on 14/17 islands sampled in the Wallacea region of Indonesia and several islands off the west coast of Perth. Increases in international tourism, involving islands such as Bali, have resulted in the isolation of a high proportion of exotic serovar infections suggesting that densely populated island resorts in the Asian region are acting as staging posts for the interchange of Salmonella infections between tropical and temperate regions.

Salmonella infections in Antarctic fauna and island populations of wildlife exposed to human activities in coastal areas of Australia.

Salmonella infections in Antarctic wildlife were first reported in 1970 and in a search for evidence linking isolations with exposure to human activities, a comparison was made of serovars reported from marine fauna in the Antarctic region from 1982-2004 with those from marine mammals in the Northern hemisphere. This revealed that 10 (83%) Salmonella enterica serovars isolated from Antarctic penguins and seals were classifiable in high-frequency (HF) quotients for serovars prevalent in humans and domesticated animals. In Australia, 16 (90%) HF serovars were isolated from marine birds and mammals compared with 12 (86%) HF serovars reported from marine mammals in the Northern hemisphere. In Western Australia, HF serovars from marine species were also recorded in humans, livestock, mussels, effluents and island populations of wildlife in urban coastal areas. Low-frequency S. enterica serovars were rarely detected in humans and not detected in seagulls or marine species. The isolation of S. Enteritidis phage type 4 (PT4), PT8 and PT23 strains from Adélie penguins and a diversity of HF serovars reported from marine fauna in the Antarctic region and coastal areas of Australia, signal the possibility of transient serovars and endemic Salmonella strains recycling back to humans from southern latitudes in marine foodstuffs and feed ingredients.

Salmonella infections in a marsupial, the quokka (Setonix brachyurus), in relation to seasonal changes in condition and environmental stress.

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.

The natural history of salmonellae in mammals of the tropical Kimberley region, Western Australia.

Screening for salmonellae was conducted on five occasions within a year on mammals from many different habitats in the Mitchell Plateau area of the tropical Kimberley Division of Western Australia. Some data were obtained from reptiles. Forty-two Salmonella serotypes, two Edwardsiella and one Arizona strain were isolated. Marsupials harbour significantly more (1.6 times) Salmonella serotypes than eutherians. Eleven Salmonella serotypes and one Arizona strain were isolated from reptiles. All Salmonella strains were common to the mammalian species. Varanid lizards showed higher prevalence of salmonellae than other reptilian families. Top carnivores (reptile and marsupial) show relatively high numbers of Salmonella serotypes and prevalence levels. Four mammalian species showed marked seasonal variation in the prevalence of salmonellae and three species in the number of serotypes isolated. Pooled mammalian community data for individual survey sites showed similar seasonal variation which reflected the pattern seen in the predominant host species on the site. Significant seasonal variation in the prevalence of salmonella was concurrent in three of the host species showing maximum prevalence in the wet season (January-summer) followed by a declining prevalence to the end of the dry season (October). Prevalence in the fourth species was also high in January, but continued to increase after the wet season (April) before decreasing as the dry season progressed (July and October). Dendrograms of association showed that the salmonella 'community' does not associate according to any systematic category of the hosts and no evidence of such communities was found using other criteria, such as site or coastal vs inland locations. No evidence was found for host or site specificity of given serotypes. Multiple serotype infections by salmonella were common, with up to three present in mammals and reptiles, and they occurred at random. When hosts in coastal habitats were compared with those in inland sites higher, lower or no difference was found in the prevalence of salmonella, depending upon which host was considered. Sites with similar mammals and vegetation sometimes showed marked differences in salmonella prevalence at a given time. Generally a given Salmonella serotype was lost from the host within congruent to 3 months. Surveys for salmonellae should be designed to include a range of species, replicated vegetation types and, especially, be repeated in several seasons. Edwardsiella tarda was isolated twice from a carnivorous marsupial.

Serum and plasma zinc, copper and iron concentrations in Aboriginal communities of North Western Australia.

Two aboriginal communities situated in the tropical north-west of the Australian continent have been investigated in regard to trace metal status (zinc, copper, and iron) and other laboratory and epidemiological information. A total of 364 persons, ranging in age from 5 to 77 years were studied. The incidence of hypozincemia (serum or plasma zinc concentration less than 0.71 micrograms/ml) of the two communities when combined was 24.4%, while hypercupremia (defined as serum or plasma copper levels greater than 1.38 micrograms/ml) was 47.9%. Depressed serum iron levels were demonstrated in more than 50% of the Aborigines studied. Hypozincemia was most prevalent (incidence 31 to 67%) in children at the time of the important pre- and postadolescent growth period (10 to 15 years) and in women beyond 60 years of age (incidence 33 to 64%). Serum total protein and vitamin B12 levels tended to be increased. Mild anemia was seen in approximately one in five persons aged less than 20 years. Intestinal parasites and pathogenic enterobacteria were frequently isolated in fecal specimens. In one community, half of the persons examined had positive isolates of enteric pathogens. Intestinal parasites predominated and were more frequently isolated from persons aged less than 20 years. Ancylostoma duodenale accounted for 32% of the pathogens isolated. Evidence is presented that suggests that both communities are exposed to numerous bacterial, viral, and parasitic infections. The diet consumed in these communities is predominately white flour and refined sugar. Geophagia is practiced in this area of Australia. It is emphasied that all the etiological prerequisites and many of the laboratory findings ascribed to the zinc deficiency syndrome appear to be operating in the two Aboriginal communities studied.

Human salmonella carriers in a tropical urban environment.

Salmonella sp. were isolated from rectal swab specimens from 39 to 464 (8.4%) of apparently healthy adults and children in central Jakarta, Indonesia. A wide variety of species of Salmonella were found with S. oranienburg predominating. Most of the S. oranienburg isolated were resistant to a wide range of antibiotics, probably because of their previous widespread and inappropriate administration. The yield of carriers identified increased significantly with the use of double enrichment procedures. This study emphasizes the importance of high rates of carriage of Salmonella sp. as potential causes of diarrhoeal disease in overcrowded, unhygienic cities in the tropics.

Faecal pollution of surface waters in Jakarta.

Profuse numbers of Enterobacteriaceae were found in samples of surface waters from the Ciliwung River and adjoining canals which criss-cross metropolitan Jakarta and are used widely for domestic purposes by the poorer sections of its population. 15 of the 20 specimens gres E. coli, Klebsiella were isolated from seven and Citrobacter from four. Using enrichment culture procedures, Salmonella sp. were grown from 10 (48%) of 21 water samples examined, and 12 (63%) of aquatic sediments collected at the same sites. Altogether 14 serotypes and 37 Salmonella isolations were recorded. This high degree of faecal contamination of the environment is a major cause of the immense problem of gastro-intestinal infections in that city and probably in many similar cities in developing countries in the tropics.

Salmonella javiana infection in an infant associated with a marsupial, the quokka, Setonix brachyurus, in Western Australia.

Salmonella 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.

Enrichment procedures for the isolation of Salmonella, Arizona, Edwardsiella and Shigella from faeces.

Strontium selenite A broth incubated at 37 degrees C., and strontium chloride B broth incubated at 43 degrees C., have been found an effective combination for the isolation of Salmonella, Arizona and Edwardsiella from human faeces.Direct plating on deoxycholate citrate agar was superior to enrichment methods for the isolation of Shigella species.Strontium selenite A broth was suitable for the isolation of Salmonella and Arizona bacteria at both 37 degrees and 43 degrees C.Strontium chloride B broth incubated at 43 degrees C. was best for the isolation of Salmonella and Edwardsiella.Modified bismuth sulphite agar, although superior to D.C. agar for the growth of Salmonella and Arizona bacteria, was unsuitable for Edwardsiella and Shigella species.A considerable difference was observed in the distribution of Salmonella, Arizona and Edwardsiella serotypes isolated from humans in remote areas, when compared with isolations from more densely populated urban and agricultural centres.Epidemiological and zoogeographical aspects of host-parasite associations between humans, animals and pathogenic Enterobacteriaceae in Western Australia are discussed.

An evaluation of strontium chloride, Rappaport and strontium selenite enrichment for the isolation of salmonellas from man, animals, meat products and abattoir effluents.

Strontium chloride enrichment broth was found to be comparable to Rappaport broth for the recovery of a wide range of Salmonella serotypes from man, animals, meat products and effluents. With the exception of cloacal samples from reptiles, both procedures were superior to selenite F.The performance of strontium chloride Mand selenite F enrichment was improved when effluent samples were incubated at 43 degrees C.Strontium chloride M and Rappaport enrichment were superior to selenite F for the isolation of Arizona species from reptiles.Strontium chloride B, strontium selenite and Rappaport broths were found suitable for the isolation of multiple Salmonella serotypes from sea water contaminated with abattoir effluents. The strontium chloride B and strontium selenite enrichment media were superior to Rappaport broth when samples were incubated at 43 degrees C.Modified bismuth sulphite agar was found superior to Salmonella-Shigella agar as a solid subculture medium.The investigation of a food poisoning outbreak due to Salmonella typhimurium phage type 21 is reported.The significance of the choice of sampling and isolation techniques in salmonellosis in man and animals is discussed.

Strontium chloride B and E.E. enrichment broth media for the isolation of Edwardsiella, Salmonella and Arizona species from tiger snakes.

Strontium 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.

A comparative trial of Rappaport enrichment medium for the isolation of Salmonellae from faeces.

Seven-thousand-and-thirty-six specimens of faeces were examined for Salmonellae using three enrichment culture media in parallel.Rappaport's magnesium chloride malachite green broth medium proved superior to selenite F and tetrathionate broths in the recovery of a wide variety of Salmonella serotypes. However, it was inferior to selenite broth in the recovery of Salmonella typhi.A higher recovery rate of Salmonellae was obtained from undiluted than from 1: 1,000 dilution of faeces.