virus in bloodstream

virus blood bloodstream aorta capillary cell cells cellules circulatory clot corpuscle electron epidemic erythrocytes erythroid flock flow flu formation germ germs group haematids hematology hemoglobin immun immune immunity immunize influenza medical medicine microbes microbiology microscopic microscopy outbreak pathogen red scanning science spherical stream system vaccine vascular vein viral viruses viremia term enter parasitic meaning rely outside host survival reproduction leading minuscule 000 times smaller width human hair bloodstream reproduction viremia hair