Salmonella types isolated from the gulf of Aarhus compared with types from infected human beings, animals, and feed products in Denmark.

A 2-year examination for Salmonella was conducted in the gulf of Aarhus, which receives waste water from local industries and from about 100,000 inhabitants. An approximately rectilinear relationship is shown between the most probable number of Escherichia coli and species of Salmonella. Salmonella species can be demonstrated with the same frequency in inlets and outlets of the treatment plants. Data on the distribution of Salmonella types in the gulf of Aarhus and in Oeresound outside Copenhagen (1 million inhabitants) in 1966 and 1968 and the distribution in man, animals, and feeding stuff during the period 1960 to 1968 in Denmark as a whole are shown. This indicates that the classical chain of infection (feed stuff-animals-food-man) is without importance in Denmark, and that a great nlumber of the human cases may be due to increasing communication, because severa of the demonstrated types have been found neither in feed stuff nor in animals in this period. We suggest that E. coli counts, currently used in examination of waters receiving effluents of streams and sewage treatment plants, should be supplemented at intervals with qualitative Salmonella examinations.