Friend virus severity is associated with male mouse social status and environmental temperature.

Pathogen virulence is highly variable within populations, and although many factors contributing to virulence differences are known, there is still much variation left unexplained. Identifying and characterizing environmental conditions associated with different virulence levels is therefore an important undertaking in infectious disease research. One factor considered to be a major determinant of overall health and susceptibility to disease in social animals is social status.

Deep Sequencing of MHC-Adapted Viral Lines Reveals Complex Recombinational Exchanges With Endogenous Retroviruses Leading to High-Frequency Variants.

Experimental evolution (serial passage) of Friend virus complex (FVC) in mice demonstrates phenotypic adaptation to specific host major histocompatibility complex (MHC) genotypes. These evolved viral lines show increased fitness and virulence in their host-genotype-of-passage, but display fitness and virulence tradeoffs when infecting unfamiliar host MHC genotypes. Here, we deep sequence these viral lines in an attempt to discover the genetic basis of FVC adaptation.