This study looked at single nucleotide polymorphisms (SNPs) as possible genetic markers or defects that weaken disease resistance to different pathogenic agents. The objectives of this study were to determine the effects of lectin gene defects on susceptibility of pigs to typical infections, especially in PRRS, to determine which of these genes were associated with reduced growth performance, and to modify genetic tests so they can be used on archived tissue samples from pigs with various diseases diagnosed after a pig has died or been slaughtered. Researchers developed 27 single SNPs in 15 innate immune genes of pigs. This was used to search for SNP and disease associations in 464 pigs diagnosed with diseases and then being compared to 1283 normal pigs. It was confirmed that some SNPs in lectin genes are associated with increased occurrences of pneumonia and enteritis caused by carious agents. Evidence was also obtained for associations between SNPs in pigs with neonatal diarrhea due to E.coli. These ongoing studies have revealed several SNPs that could be useful in genetic selection against minor alleles associated with some common infectious diseases.