Epidemic 11 : An unusual increase in the number, or the appearance of a significant number, of cases of an infectious disease introduced in a region or population that is normally free from that disease
Ministry of Business, Innovation and Employment, Glossary of terms and acronyms, Wellington, New Zealand 2010. http://wwwsosh.govt.nz/resources/glossary-u.shtml, (Occupn Hlth and Sfty - Brit) {530}