PMID- 12760477
OWN - NLM
STAT- MEDLINE
DCOM- 20030812
LR  - 20181113
IS  - 0830-9000 (Print)
IS  - 0830-9000 (Linking)
VI  - 67
IP  - 2
DP  - 2003 May
TI  - Strain predominance following exposure of vaccinated and naive pregnant gilts to 
      multiple strains of porcine reproductive and respiratory syndrome virus.
PG  - 121-7
AB  - Two studies were performed in order to test the relative ability of different 
      strains of porcine reproductive and respiratory syndrome virus (PRRSV) to 
      replicate and cross the placental barrier in pregnant gilts. Study 1 comprised 6 
      nonvaccinated gilts. Study 2 comprised 8 nonvaccinated gilts and 12 gilts that 
      were vaccinated twice before conception. On, or about, gestation day 90 all gilts 
      were simultaneously exposed to 20 field strains of PRRSV (all strains were 
      distinguishable by restriction fragment length polymorphism (RFLP) patterns). 
      Gilts of study 1 were euthanized on day 7 postpartum. Gilts of study 2 were 
      euthanized on, or about, gestation day 111. All gilts, pigs, and fetuses were 
      tested for the presence and type of strain of PRRSV. Of 128 samples shown to 
      contain PRRSV, 118 contained a single strain, 4 contained 2 strains, and 2 
      contained a strain or strains for which the RFLP pattern was undecipherable. Only 
      8 of the 20 strains were isolated from nonvaccinated gilts and their litters. And 
      only 2 of the 20 strains (notably 2 of the same strains isolated from 
      nonvaccinated gilts and their litters), were isolated from vaccinated gilts and 
      their litters. Moreover, 1 of the 2 strains accounted for most (31 of 37; 84%) of 
      the isolates from the vaccinated group. Collectively these results indicate that 
      strains differ in their ability to replicate in pregnant gilts and cross the 
      placental barrier. And they suggest that maternal immunity, although sometimes 
      insufficient to prevent transplacental infection, can exert additional selective 
      pressure.
FAU - Lager, Kelly M
AU  - Lager KM
AD  - Virus and Prion Diseases of Livestock Research Unit, National Animal Disease 
      Center, USDA, Agricultural Research Service, 2300 Dayton Avenue, P.O. Box 70, 
      Ames, Iowa 50010, USA. klager@nadc.ars.usda.gov
FAU - Mengeling, William L
AU  - Mengeling WL
FAU - Wesley, Ronald D
AU  - Wesley RD
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Canada
TA  - Can J Vet Res
JT  - Canadian journal of veterinary research = Revue canadienne de recherche 
      veterinaire
JID - 8607793
RN  - 0 (Antibodies, Viral)
RN  - 0 (Vaccines, Attenuated)
RN  - 0 (Viral Vaccines)
SB  - IM
MH  - Animals
MH  - Animals, Newborn
MH  - Antibodies, Viral/blood
MH  - Female
MH  - Immunity, Maternally-Acquired
MH  - Infectious Disease Transmission, Vertical/prevention & control/*veterinary
MH  - Male
MH  - Maternal-Fetal Exchange
MH  - Polymorphism, Restriction Fragment Length
MH  - Porcine Reproductive and Respiratory Syndrome/classification/pathology/prevention 
      & control/*transmission
MH  - Porcine respiratory and reproductive syndrome 
      virus/immunology/pathogenicity/*physiology
MH  - Pregnancy
MH  - Pregnancy Complications, Infectious/*veterinary/virology
MH  - Specific Pathogen-Free Organisms
MH  - Swine
MH  - Vaccination/veterinary
MH  - Vaccines, Attenuated
MH  - Viral Vaccines
PMC - PMC227039
EDAT- 2003/05/23 05:00
MHDA- 2003/08/13 05:00
PMCR- 2003/08/01
CRDT- 2003/05/23 05:00
PHST- 2003/05/23 05:00 [pubmed]
PHST- 2003/08/13 05:00 [medline]
PHST- 2003/05/23 05:00 [entrez]
PHST- 2003/08/01 00:00 [pmc-release]
AID - 0000000-200305000-00007 [pii]
PST - ppublish
SO  - Can J Vet Res. 2003 May;67(2):121-7.