Contagiousness

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The term contagiousness , infectiousness , infectiousness or ability to transmit , describes the degree of the ability of a pathogen to transmit a pathogen, or a person infected by this pathogen, through direct or indirect contact between living beings and living beings and describes how easily or difficult the pathogen is to the various , each pathogen-typical infection path can be transmitted, for example from a wound , a body secretion or via a breath-related aerosol . Contagiousness is therefore an indication of the size of the possibility of transferring it to other people upon contact with this pathogen from an affected area. Contagiousness is determined, among other things, by the number of newly formed pathogens per cell determined in the laboratory ( burst size , resulting in a dose , sometimes instead of a titer ), the minimum infection dose and the epidemiological R 0 value (see also base reproduction number ) of the pathogen. A measure of the infectivity (contagious) of a pathogen at the initial contact is the Kontagiositätsindex . This describes the proportion of a non- immune population in which an infection occurs after contact with a pathogen .

The infectivity , however, describes the ability of a pathogen, a host also after transfer infect . It is characterized, among other things, by the host's defense mechanisms (host restriction) and by the adaptation of the pathogen to the host's cellular and immunological processes ( host adaptation) . These two factors are also reflected in the minimum infectious dose and in the R 0 value, but are independent of the dose. In English usage, however, the terms contagious '(Engl. Contagiosity ) and infectivity' (Engl. Infectivity ) equivalent.

See also

literature

  • Susanne Modrow, Dietrich Falke , Uwe Truyen: Molecular Virology. An introduction for biologists and medical professionals. 2nd Edition. Spectrum textbook, Heidelberg 2002, ISBN 3-8274-1086-X (with references, English translation 2006) .
  • David M. Knipe, Peter M. Howley, et al. (eds.): Fields' Virology (= standard work in virology. ). 2 volumes, 5th edition, Lippincott Williams & Wilkins, Philadelphia 2007, ISBN 978-0-7817-6060-7 .

Individual evidence

  1. ↑ a b c Wolfgang Kiehl: Infection protection and infection epidemiology. Technical terms - definitions - interpretations. Ed .: Robert Koch Institute, Berlin 2015, ISBN 978-3-89606-258-1 , p. 81, keyword contagiosity
  2. ↑ Contagiousness on pschyrembel.de
  3. ↑ Contagious Origin and Meaning of the Word . Retrieved March 11, 2012.