plague

noun

an annoyance
“those children are a damn plague”
any large scale calamity (especially when thought to be sent by God)
a swarm of insects that attack plants
“a plague of grasshoppers”
infestation
any epidemic disease with a high death rate

pest
a serious, sometimes fatal, infection of rodents caused by Yersinia pestis and accidentally transmitted to humans by the bite of a flea that has bitten an infected animal
“Millions of people died in the plague outbreaks of the middle ages.”
pest

verb