In
epidemiology
Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and Risk factor (epidemiology), determinants of health and disease conditions in a defined population, and application of this knowledge to prevent dise ...
, infectivity is the ability of a
pathogen
In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a Germ theory of d ...
to establish an infection. More specifically, infectivity is the extent to which the pathogen can enter, survive, and multiply in a host. It is measured by the ratio of the number of people who become infected to the total number exposed to the pathogen.
Infectivity has been shown to
positively correlate with
virulence, in plants. This means that as a pathogen's ability to infect a greater number of hosts increases, so does the level of harm it brings to the host.
A pathogen's infectivity is different from its
transmissibility, which refers to a pathogen's capacity to pass from one organism to another.
See also
*
Basic reproduction number (basic reproductive rate, basic reproductive ratio, ''R''
0, or ''r nought'')
References
Epidemiology
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