PMID- 17472459
OWN - NLM
STAT- MEDLINE
DCOM- 20070628
LR  - 20220321
IS  - 0002-9645 (Print)
IS  - 0002-9645 (Linking)
VI  - 68
IP  - 5
DP  - 2007 May
TI  - Effect of vaccination with a modified-live porcine reproductive and respiratory 
      syndrome virus vaccine on dynamics of homologous viral infection in pigs.
PG  - 565-71
AB  - OBJECTIVE: To determine effects of vaccination protocols with modified-live 
      porcine reproductive and respiratory syndrome virus (PRRSV) vaccine on 
      persistence and transmission of virus in pigs infected with a homologous isolate 
      and determine clinical and virologic responses following heterologous viral 
      challenge. ANIMALS: Four hundred forty 6- to 8-week-old PRRSV-naive pigs. 
      PROCEDURES: Pigs were allocated into 5 groups. Groups A to D were inoculated with 
      wild-type PRRSV VR2332. Group A (positive control pigs) received PRRSV only. 
      Groups B, C, and D received modified-live PRRSV vaccine (1, 2, or 3 doses). Group 
      E served as a negative control group. To evaluate viral transmission, sentinel 
      pigs were introduced into each group at intervals from 37 to 67, 67 to 97, and 97 
      to 127 days postinoculation (DPI). To evaluate persistence, pigs were euthanized 
      at 37, 67, 97, or 127 DPI. To assess clinical and virologic response after 
      challenge, selected pigs from each group were inoculated at 98 DPI with a 
      heterologous isolate (PRRSV MN-184). RESULTS: Mass vaccination significantly 
      reduced the number of persistently infected pigs at 127 DPI. Vaccination did not 
      eliminate wild-type PRRSV; administration of 2 or 3 doses of modified-live virus 
      vaccine reduced viral shedding after 97 DPI. Previous exposure to wild-type and 
      vaccine virus reduced clinical signs and enhanced growth following heterologous 
      challenge but did not prevent infection. CONCLUSIONS AND CLINICAL RELEVANCE: 
      Findings suggest that therapeutic vaccination may help to reduce economic losses 
      of PRRSV caused by infection; further studies to define the role of modified-live 
      virus vaccines in control-eradication programs are needed.
FAU - Cano, Jean Paul
AU  - Cano JP
AD  - Swine Disease Eradication Center, College of Veterinary Medicine, University of 
      Minnesota, Saint Paul, MN 55108, USA.
FAU - Dee, Scott A
AU  - Dee SA
FAU - Murtaugh, Michael P
AU  - Murtaugh MP
FAU - Trincado, Carlos A
AU  - Trincado CA
FAU - Pijoan, Carlos B
AU  - Pijoan CB
LA  - eng
PT  - Controlled Clinical Trial
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Am J Vet Res
JT  - American journal of veterinary research
JID - 0375011
RN  - 0 (Viral Vaccines)
SB  - IM
MH  - Animals
MH  - Porcine Reproductive and Respiratory Syndrome/immunology/*prevention & 
      control/*virology
MH  - Porcine respiratory and reproductive syndrome virus/*immunology
MH  - Swine/immunology/virology
MH  - Viral Vaccines/administration & dosage/*immunology
EDAT- 2007/05/03 09:00
MHDA- 2007/06/29 09:00
CRDT- 2007/05/03 09:00
PHST- 2007/05/03 09:00 [pubmed]
PHST- 2007/06/29 09:00 [medline]
PHST- 2007/05/03 09:00 [entrez]
AID - 10.2460/ajvr.68.5.565 [doi]
PST - ppublish
SO  - Am J Vet Res. 2007 May;68(5):565-71. doi: 10.2460/ajvr.68.5.565.