Parasitism - A close relationship between two organisms in which one organism, the parasite, benefits at the expense of the host organism.⏎
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.⏎
Reservoir - An organism in which a parasite that is pathogenic for some other organism lives and reproduces without harming its host.⏎
Replication - The process of producing a copy of a strand of DNA.⏎