Quantifying relative virulence: when μ max fails and AUC alone just is not enough

• Published in: Journal of general virology Vol. 102; no. 1
• Main Authors: Ceballos, Ruben Michael, Stacy, Carson Len
• Format: Journal Article
• Language: English
• Published: England Microbiology Society 2021
• Subjects: Archaea - growth & development; Archaea - virology; Area Under Curve; Fuselloviridae - growth & development; Fuselloviridae - pathogenicity; Host-Pathogen Interactions; Models, Biological; Short Communication; Virology - methods; Virulence; Virus Replication; Viruses - growth & development; Viruses - pathogenicity; Gompertz model; relative virulence; non-lytic viruses; virus–host dynamicsx; Sulfolobus spindle-shaped virus; growth curve analysis
• ISSN: 0022-1317; 1465-2099; 1465-2099
• DOI: 10.1099/jgv.0.001515

A challenge in virology is quantifying relative virulence ( V R ) between two (or more) viruses that exhibit different replication dynamics in a given susceptible host. Host growth curve analysis is often used to mathematically characterize virus–host interactions and to quantify the magnitude of detriment to host due to viral infection. Quantifying V R using canonical parameters, like maximum specific growth rate ( μ max ), can fail to provide reliable information regarding virulence. Although area-under-the-curve (AUC) calculations are more robust, they are sensitive to limit selection. Using empirical data from Sulfolobus Spindle-shaped Virus (SSV) infections, we introduce a novel, simple metric that has proven to be more robust than existing methods for assessing V R . This metric ( I SC ) accurately aligns biological phenomena with quantified metrics to determine V R . It also addresses a gap in virology by permitting comparisons between different non-lytic virus infections or non-lytic versus lytic virus infections on a given host in single-virus/single-host infections.