epidemicity

ep·i·de·mic·i·ty

noun
\ˌep-ə-ˌdem-ˈis-ət-ē, ˌep-əd-ə-ˈmis-\

plural ep·i·de·mic·i·ties

Definition of EPIDEMICITY

: the quality or state of being epidemic; specifically : the relative ability to spread from one host to others <the epidemicity of typhoid bacteria>