Pathologic Evaluation of Type 2 Porcine Reproductive and Respiratory Syndrome Virus Infection at the Maternal-Fetal Interface of Late Gestation Pregnant Gilts
March 11, 2016 —
The pathogenesis of fetal death caused by porcine reproductive and respiratory syndrome virus (PRRSV) remains unclear. The objective of this study was to improve our understanding of the pathogenesis by assessing potential relationships between specific histopathological lesions and PRRSV RNA concentration in the fetuses and the maternal-fetal interface. Pregnant gilts were inoculated with PRRSV (n = 114) or sham inoculated (n = 19) at 85±1 days of gestation. Dams and their litters were humanely euthanized and necropsied 21 days later. PRRSV RNA concentration was measured by qRT-PCR in the maternal-fetal interface and fetal thymus (n = 1391). Presence of fetal lesions was positively related to PRRSV RNA concentration in the maternal-fetal interface and fetal thymus (P<0.05 for both), but not to the distribution or severity of vasculitis, or the severity of endometrial inflammation. The presence of fetal and umbilical lesions was associated with greater odds of meconium staining (P<0.05 for both). The distribution and severity of vasculitis in endometrium were not significantly related to PRRSV RNA concentration in maternal-fetal interface or fetal thymus. Endometrial inflammation severity was positively related to distribution and severity of vasculitis in endometrium (P<0.001 for both). Conclusions from this study suggest that type 2 PRRSV infection in pregnant gilts induces significant histopathological lesions at maternal-fetal interface, but they are not associated with presence of PRRSV in the maternal-fetal interface at 21 days post infection. Conversely, fetal pathological lesions are associated with presence of PRRSV in the maternal-fetal interface and fetal thymus, and meconium staining is significantly associated with the presence of both fetal and umbilical lesions observed 21 days post infection.
Novakovic P, Harding JC, Al-Dissi AN, Ladinig A, Detmer SE; Pathologic Evaluation of Type 2 Porcine Reproductive and Respiratory Syndrome Virus Infection at the Maternal-Fetal Interface of Late Gestation Pregnant Gilts; PLoS One. 2016 Mar 10;11(3):e0151198. doi: 10.1371/journal.pone.0151198. PMID: 26963101
- Next story: NPPC Offers Externships for Senior Veterinary Students: Fall 2016 and Spring 2017
- Next in category: Modeling the Transboundary Risk of Feed Ingredients Contaminated with Porcine Epidemic Diarrhea Virus
- Previous in category: Association between Influenza A Virus Infection and Pigs Subpopulations in Endemically Infected Breeding Herds
- Previous story: You Need a Ticket to Fly the Coop