Protozoa - A taxonomic group of single-celled microorganisms that live in almost every kind of habitat and include some pathogenic parasites of humans and other animals. ⏎
Nanometer - A unit of length equal to one one-billionth (1 x 10-9) of a meter.⏎
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.⏎
Pathogen - A biological agent that causes disease.⏎
Rheumatic Fever - An inflammatory disease that may be caused by an untreated or improperly treated case of strep throat.⏎