By calling 01 267 50 38, AGES staff call people in Salzburg who have already been contacted by the health authorities. In contrast to contact tracing by the authorities, which is about quickly finding contact persons, the survey by AGES tries to find out the origin of the infection - the source. This data is, of course, collected anonymously. During the interviews by AGES, more detailed information on the onset of the disease, symptoms, with whom the infected person had contact in the 14 days before the onset of the disease or positive test result, etc. should be collected. There may have been contact with a person who tested positive; if not, leisure activities, workplace or sports may provide clues as to where the infection occurred: By linking these data, it may be possible to detect previously unknown clusters of cases, so-called clusters. A high rate of detection of where and how people become infected with coronavirus is important for controlling the epidemic in Austria: each response from this AGES survey makes a significant contribution to understanding how Covid 19 spreads through the population. AGES source tracing: by calling 01 267 50 38, AGES staff will contact people in Salzburg who have tested positive between 7:30 a.m. and 8:30 p.m. Monday through Friday and between 9 a.m. and 6 p.m. on Saturday and Sunday.