The objective of this research was to determine if there is genetic influence on the resistance or susceptibility to PRRSV-induced disease and lesions. Pigs of three breeds from two or three litters per breed were randomly assigned to treatment or control groups. Treatment consisted of inoculation with a well characterized, high virulence strain (VR2385) of PRRSV. Duroc, Hampshire, and Meishan pigs were weaned at 9-10 days of age and inoculated with PRRSV at 22-38 days of age. Animals were housed and cared for according to approved animal use and care standards. Pigs were inoculated intranasally with 5 ml of cell culture media containing 105.8 TCID50 of PRRSV VR2385. Controls were mock-infected. Clinical disease scores and rectal temperatures were recorded daily. Macroscopic lung lesion scores were estimated at necropsy at 10 days post inoculation. All organ systems were examined microscopically in a blinded fashion. Serum antibody response was measured by an indirect immunofluorescence assay. Hampshire pigs had significantly more severe macroscopic lung lesion scores (43.0 ± 3.7) than Duroc (29.43 ± 3.3) or Meishan (25.0 ± 3.5) pigs. Meishan pigs had significantly less PRRSV antigen detected in the lungs. Significantly more Meishan pigs had myocarditis and encephalitis. Duroc pigs had significantly lower normalized serum antibody titres to PRRSV. Differences in severity and distribution of PRRSV-induced lesions, and in normalized serum antibody response to PRRSV may be in part influenced by pig genetic factors. The ability to select animals which are less susceptible to the devastating consequences of PRRSV infection would be of tremendous value to the swine industry.
|Original language||English (US)|
|Number of pages||9|
|Journal||Journal of Animal Breeding and Genetics|
|State||Published - 1998|
ASJC Scopus subject areas
- Food Animals
- Animal Science and Zoology