| Abstract: | Previous studies have shown that the quokka (Setonix brachyurus: Marsupialia) experiences a very extensive proliferation of Salmonella infections on Rottnest Is. (Western Australia) in association with seasonal starvation in a disturbed environment. The study reported here examined the distribution of the serotypes involved, the interaction of Salmonella with other hosts, and the resulting environmental contamination. In the quokka, the serotypes were found to be significantly non-random in their distribution between areas (regardless of a seasonal cycle of infection rate in some areas) and between seasons. No one serotype showed a particular affinity for the quokka in the most adverse season. Study of the largest deviations showed that they could have been due to local amplification of particular serotypes in other hosts. It was not generally possible to distinguish the native and exotic serotypes as groups, and each serotype needed to be studied in terms of its own ecology. Environmental contamination is extensive due to proliferation of Salmonella in quokkas, but the interactions with other hosts were found to be important in determining the local distribution of serotypes. The results of this study are discussed in terms of the significance of the distribution of Salmonella in natural and disturbed areas in Western Australia, and of management of the problems created by proliferation of Salmonella in the Rottnest Is. quokka. |
