Genetic analysis of resistance to lethal infections of vesicular stomatitis virus in Syrian hamsters.

Vesicular stomatitis virus (VSV), Indiana serotype, causes a lethal disease in adult Syrian hamsters. Susceptibility to low doses of VSV (10 to 100 plaque-forming units) was shown to be genetically determined by examining six inbred strains. Three strains, LSH, MHA, and CB, were found to be extremely susceptible, with more than 70% of the animals dying within 72 h after intraperitoneal injection. Two strains, MIT and UT2, were intermediately susceptible, with approximately 60% of VSV-infected animals surviving. One strain, UT1, was found to be highly resistant; however, resistance was not acquired until the 4th or 5th week of age, and 100% of VSV-infected neonatal hamsters died. Analyses of F1 hybrid and segregant backcross populations derived from the LSH and UT1 strains suggested that at least three independent genetic loci contribute to phenotypic resistance. One locus resides on the X chromosome; the others reside on autosomes. No obvious linkage to the hamster major histocompatibility complex was detected. F1 hybrids of two highly susceptible strains, CB and MHA, were more resistant than either parental strain, suggesting that alleles of unlinked genes in the susceptible strains interact to produce a partially resistant phenotype. These alleles probably are the cause of the resistance phenotype found in the random-bred LVG strain which shares a common heritage with the CB and MHA strains.