Investigations of possible infection sources during sewer working

Aim of the study was to registrate the microbial load of sewer workers. In addition to a workplace analysis and a work-related quantitative microbial count determination, clinical examinations of 24 employees were performed. Of the workers examined one group (n = 13) was working in building maintena nce and the other one in sewer cleaning (n = 11). During high pressure clea ning procedure higher bacterial concentrations (10(4) to 10(5) colony formi ng units/m(3)) than on the outside air (10 to 10(3) colony forming units/m( 3)) were measured. Sewer workers are potentially endangered by technologica lly and climatically produced bioaerosols during high pressure cleaning pro cedure. Special preventive measures could reduce these risk. The working sa fety specialist and the workers doctor should be involved in safety assessm ent. The occupational medical attendance has to focus on the documentation of infectious diseases, vaccination status especially hepatitis A.