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. ⏎
National Institute of Allergy and Infectious Diseases (NIAID) - Part of the U.S. Department of Health and Human Services and the National Institutes of Health, NIAID conducts and supports basic and applied research to better understand, treat, and ultimately prevent infectious, immunologic, and allergic diseases.⏎
Reservoir - An organism in which a parasite that is pathogenic for some other organism lives and reproduces without harming its host.⏎
Parasitism - A close relationship between two organisms in which one organism, the parasite, benefits at the expense of the host organism.⏎
Natural Selection - The process by which certain heritable traits that contribute to the survival and reproductive success of an organism become more widespread within a population over successive generations.⏎