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Virus quantification is counting or calculating the number of virus particles (virions) in a sample to determine the virus concentration. It is used in both research and development (R&D) in academic and commercial laboratories as well as in production situations where the quantity of virus at various steps is an important variable that must be monitored.
An infectious bacterium in a food can cause various effects, such as diarrhea, vomiting, sepsis, meningitis, Guillain-Barré syndrome, and death. Most of the times, as the dose increases, the severity of the pathological effects increases, and a "dose-effect relationship" can often be established.
The serial interval in the epidemiology of communicable (infectious) diseases is the time between successive cases in a chain of transmission. [1]The serial interval is generally estimated from the interval between clinical onsets (if observable), in which case it is the 'clinical onset serial interval'.
A 2010 review study by Puren et al. [2] categorizes viral load testing into three types: (1) nucleic acid amplification based tests (NATs or NAATs) commercially available in the United States with Food and Drug Administration (FDA) approval, or on the market in the European Economic Area (EEA) with the CE marking; (2) "Home–brew" or in-house NATs; (3) non-nucleic acid-based test.
In epidemiology, infectivity is the ability of a pathogen to establish an infection. More specifically, infectivity is the extent to which the pathogen can enter, survive, and multiply in a host. It is measured by the ratio of the number of people who become infected to the total number exposed to the pathogen. [1]
When developing vaccines for viruses, the emphasis is on attenuating the virus, or decreasing its virulence, in a given host. Sometimes it is useful to employ serial passage to increase the virulence of a virus. Usually, when serial passage is performed in a species, the result is a virus that is more virulent to that species. [5]
In epidemiology, particularly in the discussion of infectious disease dynamics (mathematical modeling of disease spread), the infectious period is the time interval during which a host (individual or patient) is infectious, i.e. capable of directly or indirectly transmitting pathogenic infectious agents or pathogens to another susceptible host ...
The median infective dose (ID 50) is the number of organisms received by a person or test animal qualified by the route of administration (e.g., 1,200 org/man per oral). Because of the difficulties in counting actual organisms in a dose, infective doses may be expressed in terms of biological assay, such as the number of LD 50 s to some test ...