scientists characters in laboratory learning protozoa unicellular amoeba proteus, diseased woman with pain in stomach

protozoa unicellular amoeba proteus laboratory scientist microbiology character learning diseased woman pain stomach suffering bacteria drink food sick poisoning people vector man girl human person organism microorganism euglena protist paramecium virus cell bacteriophage germ protozoan bacillus paramecia disease parameciidae microbiota protozoology infectious bacterium microscopic microscopy science animal cause cartoon illustration