Dynamic virulence decomposition applied to house finch infection with Mycoplasma gallisepticum
Researchers built a framework that separates host and pathogen contributions to virulence across infection phases, and tested it on existing house finch data.
A study in the Proceedings of the National Academy of Sciences describes a dynamic framework for virulence decomposition. It splits virulence into host and pathogen effects and tracks how these contributions change during infection pnas.org
Proceedings of the National Academy of Sciencespnas.orgOpen source ↗. According to the authors, conventional decomposition was not designed to quantify how the contributions vary throughout an infection. The new approach combines conventional decomposition with disease space analysis.
Data and infection phases
The authors applied the framework to existing data from house finches (Haemorhous mexicanus) experimentally infected with the emerging bacterial pathogen Mycoplasma gallisepticum. They examined two biologically meaningful phases. The early phase is dominated by innate immune responses, and in the later phase the adaptive immune response is fully activated.
Results for virulence components
The analyses showed that virulence components evolved differently across the infection phases. Pathogen exploitation, per-parasite pathogenicity (PPP) and host resistance each followed a distinct trajectory. The results corroborated several known evolutionary patterns and also revealed the evolution of increased PPP in this system.
The apparent evolution of host tolerance, inferred from aggregated peak measurements, was not supported by phase-specific analyses pnas.org
Proceedings of the National Academy of Sciencespnas.orgOpen source ↗. The authors conclude that aggregated and phase-specific measures can give different mechanistic insights into virulence. They describe the framework as a general approach for quantifying how host and pathogen processes shape virulence over the course of infection.
