Index case

As an index patient, sometimes also known as Patient Zero (. Of engl Patient Zero ), is referred to in the epidemiology of the person from which the spread of a disease - does not start from or alleged output - in the majority of cases of an infectious (→ infectious disease ).

Examples

• In blood donation would be those blood donors, the index patient from whom - were transmitted pathogens ( pathogens ) to one or more recipients of his blood -derived products (→ infection ) - through its contaminated blood donation. The / Infected / s receiver and said to be determined index patient are the most important starting points for the implementation of a so-called look-back method, in which all donors of a specific recipient and all the recipients must be determined by donations of the index patient.

• In cases of suspected nosocomial infection ( " hospital infection " ), an accident at work or similar potentially infectious blood (eg, a needle stick injury ), the patient, from which the blood and / or the needle came, called an index patient.

Reconstruction of the infection routes

In the reconstruction of the spread of epidemics much you focus on the search for the index patient, so as to bring its possible contact persons and thus the propagation routes ( routes of infection ) of the pathogen in experience. How was such a search for " Patient Zero " for example, in the investigation of the SARS pandemic 2002/2003 and held at the first AIDS cases, which penetrated to the public in the early 1980s.

The best-known index patient should thereby probably the (first) called patient zero, the French Canadians Gaëtan Dugas be, from which at times we believed that the entire spread of HIV and AIDS in the United States could go back to him.

The index patient in psychotherapy

In the systemic therapy is a group member, indicating narrowing constructions of reality and unfortunately convincing patterns of interaction within the group, with its symptoms, also referred to as the index patient.