infest (v.) Look up infest at Dictionary.com
late 15c., "to attack, assail, hurt, distress, annoy," from Middle French infester, from Latin infestare "to attack, disturb, trouble," from infestus "hostile, dangerous," originally "inexorable, not able to be handled," from in- "not, opposite of" (see in- (1)) + -festus "(able to be) seized." Sense of "swarm over in large numbers" first recorded c.1600. Related: Infested; infesting.