title: Infection dynamics and clinical manifestations following experimental inoculation of gilts at 90 days of gestation with a low dose of porcine reproductive and respiratory syndrome virus.
abstract: Understanding the dynamics of porcine reproductive and respiratory syndrome virus (PRRSV) vertical transmission is important to enhance the accuracy of monitoring protocols for endemically infected breeding herds. The objectives of this study were to determine the prevalence of PRRSV within infected litters, to quantify viremia, and to identify specific attributes of infected individuals. Eight gilts were intramuscularly inoculated with 10(1) TCID(50) of a mildly virulent PRRSV strain (MN-30100) at 90 d of gestation. All inoculated gilts transmitted the virus in utero. The proportion of PRRSV PCR-positive piglets and the level of viremia in the piglets were higher at 4 d of age than at birth or at weaning. No specific attributes were associated with PRRSV infection in the piglets. This is the first report, that we are aware of, documenting the efficient in utero transmission of an extremely low dose of a mildly virulent strain of PRRSV. The results support the sampling of piglets late during lactation as a tool to monitor PRRSV shedding from sow-herds.
authors.affiliation: Swine Disease Eradication Center, University of Minnesota, College of Veterinary Medicine, St. Paul, Minnesota 55108, USA.
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Cano
authors.forename: Scott A
authors.initials: SA
authors.lastname: Dee
authors.forename: Michael P
authors.initials: MP
authors.lastname: Murtaugh
authors.forename: Albert
authors.initials: A
authors.lastname: Rovira
authors.forename: Robert B
authors.initials: RB
authors.lastname: Morrison
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000914:Antibodies, Viral / Q000097:blood; D001724:Birth Weight; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D018445:Infectious Disease Transmission, Vertical / Q000662:veterinary*; D016015:Logistic Models; D008297:Male; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology* / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics / Q000276:immunology*; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D015995:Prevalence; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D011897:Random Allocation; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D013552:Swine; D014766:Viremia / Q000276:immunology / Q000662:veterinary / Q000821:virology
chemical_list: D000914:Antibodies, Viral; D012367:RNA, Viral