in·fest 
(
ĭn-f
ĕst
)
tr.v. in·fest·ed,
in·fest·ing,
in·fests 1. To inhabit or overrun in numbers or quantities large enough to be harmful, threatening, or obnoxious: rats infesting the sewers; streets that were infested with drugs.
2. To live as a parasite in or on: livestock that were infested with tapeworms.
[Middle English infesten, to distress, from Old French infester, from Latin īnfestāre, from īnfestus, hostile; see gwhedh- in the Appendix of Indo-European roots.]
in′fes·tation n.