Infectivity

In epidemiology, infectivity is the ability of a pathogen to establish an infection. More specifically, infectivity is a pathogen's capacity for horizontal transmission that is, how frequently it spreads among hosts that are not in a parent-child relationship. The measure of infectivity in a population is called incidence.

Infectivity has been shown to positively correlate with virulence. 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.<ref>,

 An empirical study of the evolution of virulence under both horizontal and vertical transmission, 
 Evolution, 
 
 Vol. 59(Issue: 4),
 pp. 730–739,
 DOI: 10.1554/03-330,
 PMID: 15926685,</ref>

A pathogen's infectivity is subtly but importantly different from its transmissibility, which refers to a pathogen's capacity to pass from parent to child.

See also

• Basic reproduction number (basic reproductive rate, basic reproductive ratio, R₀, or r nought)

External links

• Definition