what is the protozoa
Protozoa. Protozoa are microscopic, one-celled organisms that can be free-living or parasitic in nature. They are able to multiply in humans, which contributes to their survival and also permits serious infections to develop from just a single organism.rotozoa that live in the blood or tissue of humans are transmitted to other humans by an arthropod vector (for example, through the bite of a mosquito or sand fly). Entamoeba histolytica is a protozoan. A microscope is necessary to view this parasite. Credit CDC.