Origin of infective

First recorded in 1350–1400; Middle English word from Medieval Latin word infectīvus. See infect, -ive
Related formsin·fec·tive·ness, in·fec·tiv·i·ty, nounun·in·fec·tive, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for infectivity

Historical Examples of infectivity

  • The high mortality and infectivity of this epidemic strongly suggest it.

    Peking Dust

    Ellen N. La Motte

  • Thus far I have considered the problem of marriage from the standpoint of infectivity.


    William J. Robinson

  • No doubt is any longer entertained of its infectious character, though the degree of infectivity appears to vary considerably.

  • On the infectivity of tabardillo or Mexican typhus for monkeys, and studies on its mode of transmission.

    Handbook of Medical Entomology

    William Albert Riley

British Dictionary definitions for infectivity



capable of causing infection
a less common word for infectious
Derived Formsinfectively, adverbinfectiveness or infectivity, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for infectivity



late 14c., from Latin infectivus, from infectus (see infect).

Online Etymology Dictionary, © 2010 Douglas Harper

infectivity in Medicine




Capable of producing infection; infectious.
Related formsin•fective•ness null n.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.