pathogen and viruses round minimal line

allergen amoeba bacillus background bacteria bacterial bacteriology bad cell cells chemical cholera circle circular coli color concept contaminant contaminants dangerous design disease diseased dust education element epidemiology experiment germs health healthcare hygiene icon illustration immune infected infection influenza isolated life line linear logo macro medical microbiological microbiology minimal mirco modern mold molecular molecule oraganism organism outline pandemic parasite pathogen pathogenic pollen probiotic probiotics research round science set shape sick sign silhouette small style substance symbol system technology thin vector