This study describes genetic differences in resistance/susceptibility topseudorabies virus (PrV) between European Large White and Chinese Meishan pigs,with a mapping of quantitative trait loci (QTL) obtained from a genome-wide scanin F(2) animals. Eighty-nine F(2) pigs were challenged intranasally at 12 weekswith 10(5) p.f.u. of the wild-type PrV strain NIA-3. For QTL analysis, 85microsatellite markers, evenly spaced on the 18 porcine autosomes and on thepseudoautosomal region of the X chromosome, were genotyped. All pigs developedclinical signs, i.e. fever, from 3 to 7 days p.i. The pure-bred Large Whitepigs, the F(1) and three-quarters of the F(2) animals, but none of the Meishanpigs, developed neurological symptoms and died or were euthanized. QTLs forappearance/non-appearance of neurological symptoms were found on chromosomes 9,5, 6 and 13. They explained 10.6-17.9% of F(2) phenotypic variance. QTL effectsfor rectal temperature after PrV challenge were found on chromosomes 2, 4, 8,10, 11 and 16. Effects on chromosomes 9, 10 and 11 were significant on agenome-wide level. The results present chromosomal regions that are associatedwith presence/absence of neurological symptoms as well as temperature courseafter intranasal challenge with NIA-3. The QTLs are in proximity to importantcandidate genes that are assumed to play crucial roles in host defence againstPrV.