cross section of a smallpox pathogen with cell membrane, nucleocapsid, cell wall and glycoproteins

infectious viral immune hygiene cell pandemic vaccination biology contagion microbiology microscopic smallpox infection outbreak virology medicals ill pox germ blood infected disease respiratory organism virus medicine contagious health care scientific research epidemic vaccine biological skin particle monkey microorganism membrane immunization infestation structure transmission quarantine dna 3d illustration pathogen pathogens symptoms virions eradicated cross section nucleocapsid wall glycoproteins