types of pathogens. viruses, bacteria, fungi, and protozoa

bacillus bacteria bacterial bacterium biology blood cancer care cell coli collection dermatophytes disease epidemic escherichia filamentous flu fungi fungus germ health herpes human illness illustration immune infection infections isolated medical medicine micro microbe microbiology microorganism microscopic mold organism pathogen pathogenic plasmodium protozoa replicate research set simplex types ulcer unicellular vector virus yeast yeasts