SUMMARYA total of 882 samples of settled sewage, sewage sludges and final effluents from eight sewage treatment plants were examined for the presence of salmonellas.Of these samples 68 % were positive, isolations being made most frequently from settled sewage (85 %), raw sludge (87 %) and anaerobically digested sludge (96 %).Fewer isolations were made from final effluent (24 %) and processed sludges (58 %). Samples usually contained less than 200 salmonellas/100 ml and arguments are presented that such concentrations should not lead to disease in animals if suitable grazing restrictions are followed.

Samples of sewage, sewage sludge and sewage effluent from one or more of four sewage treatment plants were examined for the presence of Leptospira, Mycobacterium, Escherichia coli, Brucella abortus and Bacillus anthracis. Brucella abortus and Bacillus anthracis were not isolated. Eleven strains of E. coli potentially enteropathogenic for calves or piglets, eight pathogenic strains of Mycobacterium and one patho;genic Leptospira strain were isolated from 101, 189 and 189 samples respectively. Sewage sludge is no;t considered to play a major part in the epidemiology of disease caused by these organisms.