The Clinical Measurement Ontology (CMO), Measurement Methods Ontology (MMO), and Experimental Condition Ontology (XCO) are currently being developed at the Rat Genome Database. For more information about these vocabularies please see Shimoyama et al. Three ontologies to define phenotype measurement data. Front Genet. 2012;3:87. Epub 2012 May 28 or contact us (http://rgd.mcw.edu/contact/index.shtml).
Any measurement in which the number of individuals in a study population that display a viral infection at a point in time or develop a viral infection within a determined period of time are compared to the total number of individuals in the study population. Often expressed as a percentage but could be expressed as a ratio. Viral infection is infection with a virus, a generally submicroscopic agent that lacks independent metabolism and is able to replicate only within a living host cell; the individual particle (virion) consists of nucleic acid (nucleoid) comprised of either DNA or RNA but not both, a protein shell (capsid), and in some but not all cases, a membranous envelope.