Infectious dose

The infectious dose (ID, also loading dose , engl. Infection dose ) describes the number of pathogens from a variety that a host has been administered.

The minimal infectious dose (MID ) is the minimum number of pathogens of a species that is necessary to trigger an infection . An immune response of the body can prevent a new disease from the same pathogen after infection through an acquired immunity . Below the minimum infectious dose, the ingestion of pathogens does not lead to ongoing infection.

The minimum infection dose is determined in a cell culture using a plaque assay or, if there is no infectable cell culture for the pathogen to be examined, in animal experiments . For most pathogens, the infectious dose is not known. Since the infection has many different influences, such as B. the general state of health of the cell culture or the test animal is subject, often shows a sigmoid dose-infection rate curve. Therefore, in the course of the statistical evaluation , the minimum infection dose is usually given with the index 50 as ID ₅₀ , i.e. the infection dose at which 50% of the cell cultures or test animals are infected. The minimum infectious dose of a pathogen is different for each virus strain and each species and is also related to the pathogenicity of the respective pathogen. For example, CMID ₅₀ ( Chimpanzee minimal infectious dose ) indicates the minimum infectious dose for chimpanzees , while MMID ₅₀ denotes that for mice . A TCD ₅₀ or TCID ₅₀ denotes the tissue culture infectious dose , i.e. the dose required to trigger an infection in 50% of the cell cultures.

literature

• S. Modrow, D. Falke, U. Truyen: Molecular Virology. 2nd edition, Spektrum, Heidelberg 2003, ISBN 3-8274-1086-X .
• DM Knipe, Peter M. Howley (Ed.): Fields Virology. 5th edition, Lippincott Williams & Wilkins, Philadelphia 2007, ISBN 0-7817-6060-7 .

Individual evidence

1. ↑ Norbert Suttorp et al. a. (Ed.): Infectious diseases: understanding, recognizing, treating . Thieme, Stuttgart 2004, ISBN 3-13-131691-8 , p. 12 .

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