Type-I interferon genotypes and severity of clinical disease in cattle inoculated with bovine herpesvirus 1.

ABSTRACT

Genomic DNA samples and health records from 98 unrelated, mixed-breed cattle inoculated with bovine herpesvirus 1 (BHV-1) were examined to determine the relationship between interferon (IFN) genotype and severity of clinical disease. Cattle were retrospectively classified as moderately or severely affected on the basis of rectal temperature, feed intake, and weight gain after intranasal inoculation of BHV-1. Southern blot analysis of 16 type-I IFN genes identified alleles at 3 IFN loci (IFNB1, IFNW4, and IFNW8) that were significantly associated with the more severe clinical phenotype (odds ratios = 4.1 [P = 0.01], 2.3 [P < 0.05] and 2.4 [P = 0.06], respectively). A second allele at the IFNB1 locus was associated with the milder disease phenotype (odds ratio = 2.9, P < 0.05). These results indicate that selective breeding programs aimed at altering the frequency of these alleles in cattle populations may potentially improve animal health and lessen the economic impact of BHV-1 infection on cattle producers.