PMID- 8989494
OWN - NLM
STAT- MEDLINE
DCOM- 19970401
LR  - 20061115
IS  - 0002-9645 (Print)
IS  - 0002-9645 (Linking)
VI  - 58
IP  - 1
DP  - 1997 Jan
TI  - Effects of a modified-live virus vaccine against porcine reproductive and 
      respiratory syndrome in boars.
PG  - 40-5
AB  - OBJECTIVES: To determine whether vaccine virus is found in serum and semen of 
      vaccinated boars, whether vaccination prevents subsequent shedding of wild-type 
      virus after challenge exposure, and whether semen and blood variables are altered 
      after vaccination or challenge exposure with wild-type virus, or both. DESIGN: 
      Throughout the 50-day postvaccination period, serum and semen from exposed boars 
      were evaluated for the presence of porcine reproductive and respiratory syndrome 
      virus (PRRSV). All boars were then challenge-exposed with PRRSV isolate VR-2332 
      and evaluated for an additional 27 days. Semen quality variables, serostatus, and 
      blood variables were monitored. ANIMALS: 7 PRRSV-seronegative adult boars. 
      PROCEDURE: Semen was collected 3 times weekly and evaluated by use of a nested 
      reverse-transcriptase polymerase chain reaction for detection of PRRSV RNA. Serum 
      was obtained weekly and evaluated by nested reverse-transcriptase polymerase 
      chain reaction, virus isolation, and PRRSV ELISA. Semen quality variables were 
      evaluated 3 times weekly, and CBC was performed weekly. RESULTS: Vaccine virus 
      was shed in the semen of all vaccinated boars, but shedding was of shorter 
      duration in 4 of 5 vaccinated boars than that generally observed after exposure 
      to wild-type virus. After challenge exposure, shedding of wild-type virus in 
      semen was shortened or eliminated in 4 of 5 vaccinated boars. Percentage of 
      forward movement and normal spermatozoal morphology and motility were 
      significantly reduced in vaccinated boars after challenge exposure. CONCLUSIONS: 
      Vaccine virus was shed in semen of vaccinated boars, but vaccination generally 
      reduced or eliminated shedding of wild-type PRRSV after challenge exposure. Semen 
      quality appeared to be less than optimal, particularly after vaccination and 
      subsequent challenge exposure with wild-type virus. CLINICAL RELEVANCE: 
      Extra-label use of the PRRSV vaccine in boars remains controversial because some 
      boars may still shed wild-type virus in semen after challenge exposure at 
      postvaccination day 50. Semen quality also appeared to be altered after 
      vaccination and subsequent challenge exposure.
FAU - Christopher-Hennings, J
AU  - Christopher-Hennings J
AD  - Animal Disease Research and Diagnostic Laboratory, South Dakota State University, 
      Brookings 57007, USA.
FAU - Nelson, E A
AU  - Nelson EA
FAU - Nelson, J K
AU  - Nelson JK
FAU - Benfield, D A
AU  - Benfield DA
LA  - eng
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - United States
TA  - Am J Vet Res
JT  - American journal of veterinary research
JID - 0375011
RN  - 0 (DNA, Viral)
RN  - 0 (RNA, Viral)
RN  - 0 (Viral Vaccines)
SB  - IM
MH  - Animals
MH  - DNA, Viral/analysis/genetics
MH  - Enzyme-Linked Immunosorbent Assay/veterinary
MH  - Male
MH  - Polymerase Chain Reaction/veterinary
MH  - Porcine Reproductive and Respiratory Syndrome/immunology/*prevention & control
MH  - Porcine respiratory and reproductive syndrome virus/*immunology/isolation & 
      purification
MH  - RNA, Viral/analysis/genetics
MH  - Semen/chemistry/virology
MH  - Sperm Motility
MH  - Spermatozoa/cytology/physiology
MH  - Swine
MH  - Vaccination/veterinary
MH  - *Viral Vaccines/immunology/standards
MH  - Virus Shedding/immunology
EDAT- 1997/01/01 00:00
MHDA- 1997/01/01 00:01
CRDT- 1997/01/01 00:00
PHST- 1997/01/01 00:00 [pubmed]
PHST- 1997/01/01 00:01 [medline]
PHST- 1997/01/01 00:00 [entrez]
PST - ppublish
SO  - Am J Vet Res. 1997 Jan;58(1):40-5.