Infectivity
The infectivity describes the ability of a pathogen , a host to infect . It is therefore dependent on the pathogenicity factors and thus on the ability of a pathogen to invade a host and to reproduce in it. Infectivity is determined, among other things, by the number of newly formed pathogens per cell ( burst size , resulting in a dose , sometimes instead of a titer ), the minimum infection dose and the epidemiological one determined in the laboratoryR 0 value of the pathogen.
The term contagiousness , on the other hand, describes how easily or difficult a pathogen can be transmitted through the various pathogen-typical infection routes . However, the terms are contagious (Engl. Contagiosity ) and infectivity (Engl. Infectivity ) in the English language equivalent.
Knowledge of the infectiousness and contagiousness of the pathogens responsible for an illness is important in order to be able to assess how an illness can behave in the event of an outbreak and whether any hygienic measures or epidemic- hygienic measures are necessary (e.g. quarantine ).
Examples
- Leprosy :
The leprosy pathogen ( Mycobacterium leprae ) has a low level of infectivity, i. In other words, long contact with the sick is usually necessary in order to become infected.
The Ebola virus, on the other hand, is highly infectious, i. In other words, a brief contact with the sick or with infectious material is enough to become infected.
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 . (2 volumes; standard work on virology) 5th edition, Lippincott Williams & Wilkins, Philadelphia 2007, ISBN 978-0-7817-6060-7 .
Individual evidence
- ↑ Contagious Origin and Meaning of the Word . Retrieved March 11, 2012.
