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నైరూప్య

Transmission and Epidemiology of Viruses

John S Tregoning

The infective concentration of a sample of virus may be measured by volumetric analysis during a outlined experimental assay system (e.g., in cell culture or AN animal model), by crucial the very best dilution (i.e., rock bottom concentration) of the sample that may still initiate AN infection, for instance, which will infect five hundredth of the cell cultures (tissue culture infective dose fifty, TCID50) or animals (lethal dose fifty, LD50; or infective dose fifty, ID50) used for measuring. It’s expressed as variety per volume, for instance, a hundred LD50 per cc. One LD50 usually represents more than one virus particle as (1) typically several of the incoming virus particles are non-infective thanks to defective assembly, genetic errors, or inactivation caused by environmental conditions, etc., and (2) typically several or most interactions between infective particles and cells don't cause a productive infection at the tissue/organ/individual level.