title: Variations in equid SLC11A1 (NRAMP1) genes and associations with Rhodococcus equi pneumonia in horses.
abstract: Rhodococcus equi is an important intracellular pathogen of horses, most commonly causing chronic, suppurative bronchopneumonia in foals. Although most foals likely are exposed to environmental R. equi within the 1st few days of life, only some develop R. equi pneumonia, and the basis of differences in susceptibility among foals currently is unknown. In this study, we investigated solute carrier family 11 member 1 (SLC11A1) gene sequences in the 5' untranslated region, exon 1, and a portion of intron 1 for variations in 3 equid species (horse, donkey, zebra) and compared variants within 3 independent horse breeding farms for associations with R. equi pneumonia by use of an age-matched case-control design. Seven novel variants in the 5'untranslated region were identified as specific for one or both of the non-horse equid species sampled. In addition, a single novel horse variant in the 5'untranslated region, -57C/T, was identified in 4 breeds. The -57C/T variant was found on 2 of the 3 farms with endemic R. equi pneumonia, representing 2 different horse breeds. Significant allelic and genotypic associations with susceptibility to R. equi pneumonia were observed for the -57C/T variant in foals from these farms. Although the functional impact of this novel variant remains to be determined, this study represents an important step in our understanding of natural resistance to R. equi foal pneumonia and other intracellular bacterial diseases affecting equids.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station 77843-4475, USA. nhalbert@cvm.tamu.edu
authors.forename: Natalie D
authors.initials: ND
authors.lastname: Halbert
authors.forename: Noah D
authors.initials: ND
authors.lastname: Cohen
authors.forename: Nathan M
authors.initials: NM
authors.lastname: Slovis
authors.forename: Jay
authors.initials: J
authors.lastname: Faircloth
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Martens
mesh_terms: D000193:Actinomycetales Infections / Q000235:genetics / Q000382:microbiology / Q000662:veterinary*; D000818:Animals; D027682:Cation Transport Proteins / Q000235:genetics*; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D014644:Genetic Variation; D006734:Horse Diseases / Q000235:genetics* / Q000382:microbiology*; D006736:Horses; D018410:Pneumonia, Bacterial / Q000235:genetics / Q000382:microbiology / Q000662:veterinary*; D016929:Rhodococcus equi; D000099173:Natural Resistance-associated Macrophage Protein 1
chemical_list: D027682:Cation Transport Proteins; D000099173:Natural Resistance-associated Macrophage Protein 1