depiction of virus particles in reproduction, submicroscopic infectious agent infecting cells of all lifeforms

agent ape pox bacterial infection biology biotechnology bird flu cell cells chemical contagion contagious contamination corona disintegrates epidemic epidemiology evolution illness immunity infected infectious lifeforms membrane microbiology organism pandemic particle particles pathogen pathogens protection receptors reproduction research respiration sick smear submicroscopic transmission transmitted viral virions virology virus species viruses depiction infecting generated