viral infection. allergy. allergic reaction. mucosal irritation. pollen, dust 3d

2019ncov abstract air allergen allergic allergy asian bacterium biology body care cell change contagious coronavirus dangerous defense disease dust epidemic exposure flu germ germs global health healthcare ill illness illustration immune infected infection inflammation intestines irritation macro medical medicine micro microbe microscope microscopic mucosal pandemic pollen pollinosis reaction research rhinitis risk science seasonal sickness spore viral virus