Fig 2.

Model for a hypothesis regarding the genetic cause of the persistent carrier state in stallions. This study shows an association of the CD3⁺ T cell susceptibility phenotype with the occurrence of the carrier state. The CD3⁺ T cell susceptibility phenotype was previously shown to be genetically determined (5). This study shows that the genetic definition of the susceptibility phenotype is imperfect based on the haplotype association. The genetic basis for this phenotype should be identified through additional genomic studies of this region.