Quantitative differences in the infectiousness and pathogenicity of 187 Salmonella serotypes or species.

The present paper makes use of the epidemiological statistical data from 372,496 salmonellae isolated in man and 63,345 isolations from non-human material, e.g. animal foodstuffs, domestic animals and food of animal origin, surface waters and drainage waters. There were a total of 187 different serotypes. The data are derived from publications of the Federal Health Office, Berlin, for the period 1972-76; the Center for Disease Control, Atlanta, Georgia for the years 1968-74; and from various publications and our own studies between 1954-76. On the basis of theoretical deduction and by inductive procedures, Salmonella quotients were derived as quantitative statistical values for the infectiousness or pathogenicity of the individual serotypes in man or in animals. They result from the relative frequency of a serotype in man in relation to the relative frequency in non-human material, in animal food or surface water. The Salmonella quotients for the pathogenicity in animals can also be calculated in a similar way. The values vary about the factor 10(5) in the individual serotypes. It is inferred from this that infectiousness and pathogenicity vary by the same order of size. The Salmonella quotients are constant over many years and evidently also all over the world for most serotypes. Salmonella quotients with numerical values less than 1 indicate a depletion of the corresponding serotype in man. Numerical values greater than 1 indicate an accumulation. Conclusions can hence be drawn with regard to lower or higher infectiousness and pathogenicity.