Epidemic
Epidemic (adj & noun) /ˌep.ɪˈdem.ɪk/
noun: an outbreak of a disease – a fast-spreading disease, plague – a rapid growth in something – outbreak – outburst – increase – prevalent – widespread:
Hundreds of people died on that island due to an epidemic of a viral disease.
Antonyms: restricted, decrease
Adverb: epidemically