TMEM154 and infection: We identified two SRLV genetic subgroups that are infecting U.S. sheep and that are distinct from SRLVs of European origins, and report that sheep with hemizygous or homozygous TMEM154 K35 genotypes have an increased risk of infection by SRLVs of subgroup 1, as do sheep with hemi-or homozygous TMEM154 E35 genotypes by SRLVs of subgroup 2.