PMID- 30529234 OWN - NLM STAT- MEDLINE DCOM- 20190122 LR - 20190122 IS - 1872-7492 (Electronic) IS - 0168-1702 (Linking) VI - 260 DP - 2019 Jan 15 TI - Classification of fetal resilience to porcine reproductive and respiratory syndrome (PRRS) based on temporal viral load in late gestation maternal tissues and fetuses. PG - 151-162 LID - S0168-1702(18)30596-3 [pii] LID - 10.1016/j.virusres.2018.12.002 [doi] AB - Although porcine reproductive and respiratory syndrome virus (PRRSV) readily crosses the maternal fetal interface (MFI) in third trimester, fetal resilience varies within litters. The aim of this study was to characterize PRRSV-2 concentration in MFI and fetuses at five time points after experimental inoculation of late gestation gilts and use this information to classify potentially resistant, resilient and susceptible fetuses. The secondary objective was to verify the relationship between PRRS viral load and intrauterine growth retardation (IUGR). Three PRRSV-inoculated pregnant gilts and 1 sham-inoculated control were euthanized at five time points in days post infection (DPI; 2, 5, 8, 12, 14). The preservation status of each fetus was determined and MFI samples adjacent to the umbilical stump of each fetus, as well as serum, thymus, umbilical cord and amniotic fluid were collected. Viral load was quantified using probe-based reverse-transcriptase quantitative PCR (RT-qPCR) targeting PRRSV NVSL 97-7895 ORF7. Our result show the MFI was largely PRRSV infected by 2 DPI and virus was first detected in fetal sera and umbilical cord by 5 DPI, and in fetal thymus and amniotic fluid by 8 DPI. This indicates that PRRSV-2 quickly crossed the placenta and traveled toward the fetus via umbilical circulation within one week of the dam's inoculation. Fetal compromise was first observed on 8 DPI and increased progressively through to 14 DPI. However, several factors were associated with fetal resilience. The random forest model identified that 'viral load in fetal thymus' and duration of infection ('DPI') as the most important factors predicting fetal resilience and resistance. Moreover, IUGR fetuses had lower viral load and were less frequently compromised or dead compared to non-IUGR and average cohorts. Understanding the mechanisms of fetal resilience to PRRSV will improve selection strategies for replacement gilts. CI - Copyright (c) 2018 Elsevier B.V. All rights reserved. FAU - Malgarin, Carolina M AU - Malgarin CM AD - Western College of Veterinary Medicine, University of Saskatchewan, S7N 5B4, Canada. Electronic address: carolina.malgarin@usask.ca. FAU - Nosach, Roman AU - Nosach R AD - Western College of Veterinary Medicine, University of Saskatchewan, S7N 5B4, Canada. Electronic address: rvn767@mail.usask.ca. FAU - Novakovic, Predrag AU - Novakovic P AD - Western College of Veterinary Medicine, University of Saskatchewan, S7N 5B4, Canada. Electronic address: predrag.novakovic@usask.ca. FAU - Suleman, Muhammad AU - Suleman M AD - Western College of Veterinary Medicine, University of Saskatchewan, S7N 5B4, Canada. Electronic address: dr.suleman.muhammad@gmail.com. FAU - Ladinig, Andrea AU - Ladinig A AD - University of Veterinary Medicine, 1210, Vienna, Austria. Electronic address: andrea.ladinig@vetmeduni.ac.at. FAU - Detmer, Susan E AU - Detmer SE AD - Western College of Veterinary Medicine, University of Saskatchewan, S7N 5B4, Canada. Electronic address: susan.detmer@usask.ca. FAU - MacPhee, Daniel J AU - MacPhee DJ AD - Western College of Veterinary Medicine, University of Saskatchewan, S7N 5B4, Canada. Electronic address: d.macphee@usask.ca. FAU - Harding, John C S AU - Harding JCS AD - Western College of Veterinary Medicine, University of Saskatchewan, S7N 5B4, Canada. Electronic address: john.harding@usask.ca. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20181205 PL - Netherlands TA - Virus Res JT - Virus research JID - 8410979 SB - IM MH - Animal Structures/*virology MH - Animals MH - *Disease Resistance MH - Female MH - Fetus/*virology MH - Porcine Reproductive and Respiratory Syndrome/*immunology/pathology/virology MH - Porcine respiratory and reproductive syndrome virus/genetics/*isolation & purification MH - Pregnancy MH - Pregnancy Complications, Infectious/immunology/pathology/*veterinary/virology MH - Real-Time Polymerase Chain Reaction MH - Swine MH - *Viral Load OTO - NOTNLM OT - Intrauterine growth retardation OT - Random forest OT - Resistance OT - Swine OT - Transmission OT - Virus EDAT- 2018/12/12 06:00 MHDA- 2019/01/23 06:00 CRDT- 2018/12/12 06:00 PHST- 2018/10/03 00:00 [received] PHST- 2018/11/30 00:00 [revised] PHST- 2018/12/04 00:00 [accepted] PHST- 2018/12/12 06:00 [pubmed] PHST- 2019/01/23 06:00 [medline] PHST- 2018/12/12 06:00 [entrez] AID - S0168-1702(18)30596-3 [pii] AID - 10.1016/j.virusres.2018.12.002 [doi] PST - ppublish SO - Virus Res. 2019 Jan 15;260:151-162. doi: 10.1016/j.virusres.2018.12.002. Epub 2018 Dec 5.