Pandemic - An increase in the occurrence of a particular disease over a very large region, such as a continent or the entire globe, that is greater than what is expected over a given period of time.⏎
Prion - A causative agent of infectious disease that is composed primarily of protein.⏎
Outbreak - An unexpected increase in the incidence of a particular disease over a given time period and geographic range. A general term that may refer either to an epidemic or a pandemic.⏎
Reproduction - The process by which parent organisms create new offspring by either sexual or asexual means.⏎