PMID- 11163670
OWN - NLM
STAT- MEDLINE
DCOM- 20010510
LR  - 20190728
IS  - 0264-410X (Print)
IS  - 0264-410X (Linking)
VI  - 19
IP  - 11-12
DP  - 2001 Jan 8
TI  - Chimeric (marker) C-strain viruses induce clinical protection against virulent 
      classical swine fever virus (CSFV) and reduce transmission of CSFV between 
      vaccinated pigs.
PG  - 1467-76
AB  - Two live recombinant vaccines (Flc9 and Flc11) against classical swine fever 
      (CSF) were evaluated for their capacity to reduce transmission of virulent CSF 
      virus (CSFV) among vaccinated pigs. In Flc9 the 5' terminal half of the E2 gene 
      of the C-strain, a CSFV vaccine strain, was exchanged with the homologous gene of 
      the bovine viral diarrhoea virus (BVDV) strain 5250, the E(rns) gene was 
      exchanged likewise in the chimeric Flc11 virus. Both recombinant vaccines induce 
      an antibody response in pigs that can be distinguished from that induced after a 
      wild-type CSFV infection. Four experiments were performed to estimate the 
      reproduction ratio R after different vaccination-challenge intervals. Each group 
      consisted of ten pigs [specified pathogen free (SPF) pigs or conventional pigs] 
      that were vaccinated once, intramuscularly, either with Flc9 or Flc11 virus or 
      that were not vaccinated. Vaccinated and susceptible pigs were challenged 
      intranasally with the virulent CSFV strain Brescia or Behring, 1, 2 or 4 weeks 
      after vaccination. Whether contact-pigs became infected was determined using a 
      CSFV specific E2 (Flc9) or E(rns) (FLc11) antibody ELISA. In the unvaccinated 
      control groups, virus secretion started from day 2 to 4 after inoculation and all 
      contact pigs became infected. Contact pigs became infected in the group of pigs 
      (SPF or conventional) vaccinated once with Flc9 virus and challenged 1-, 2- or 
      4-weeks later. The estimates of the R in the groups challenged at 1-, 2- and 
      4-weeks after vaccination were 0.38, 0 and 0.75, respectively. Contact infected 
      pigs were not detected (R=0) in any of the groups of pigs, vaccinated with Flc11, 
      only SPF pigs were used. In order to achieve a statistical significance of R 
      within the vaccinated groups each of the experiments has to be repeated at least 
      once. The R of pigs vaccinated with Flc11 virus and challenged at 1- or 2-weeks 
      after vaccination was however significantly lower that the reproduction ratio of 
      the unvaccinated groups (P=0.013). The R of pigs vaccinated with Flc9 virus and 
      challenged at 1 (conventional pigs) or 2 weeks (SPF pigs) after vaccination was 
      significantly lower that the reproduction ratio of the unvaccinated groups 
      (P=0.013). In conclusion, both chimeric viruses Flc9 and Flc11 provided good 
      clinical protection against a challenge with virulent CSFV at 1 or 2 weeks after 
      vaccination. Further experiments should be carried out to study more aspects of 
      the efficacy of these recombinant viruses before they can be used as a marker 
      vaccine under field circumstances.
FAU - de Smit, A J
AU  - de Smit AJ
AD  - Department of Mammalian Virology, Institute for Animal Science and Health 
      (ID-Lelystad), P.O. Box 65, 8200, AB Lelystad, The Netherlands. 
      a.j.desmit@id.wag-ur.nl
FAU - Bouma, A
AU  - Bouma A
FAU - van Gennip, H G
AU  - van Gennip HG
FAU - de Kluijver, E P
AU  - de Kluijver EP
FAU - Moormann, R J
AU  - Moormann RJ
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Netherlands
TA  - Vaccine
JT  - Vaccine
JID - 8406899
RN  - 0 (Antibodies, Viral)
RN  - 0 (Genetic Markers)
RN  - 0 (Vaccines, Synthetic)
RN  - 0 (Viral Vaccines)
SB  - IM
MH  - Animals
MH  - Antibodies, Viral/biosynthesis
MH  - Chimera/genetics/immunology
MH  - Classical Swine Fever/immunology/*prevention & control/transmission
MH  - Classical Swine Fever Virus/*genetics/*immunology/pathogenicity
MH  - Genetic Markers
MH  - Swine
MH  - Vaccination/veterinary
MH  - Vaccines, Synthetic/pharmacology
MH  - Viral Vaccines/pharmacology
MH  - Virulence
EDAT- 2001/02/13 11:00
MHDA- 2001/05/22 10:01
CRDT- 2001/02/13 11:00
PHST- 2001/02/13 11:00 [pubmed]
PHST- 2001/05/22 10:01 [medline]
PHST- 2001/02/13 11:00 [entrez]
AID - S0264-410X(00)00347-9 [pii]
AID - 10.1016/s0264-410x(00)00347-9 [doi]
PST - ppublish
SO  - Vaccine. 2001 Jan 8;19(11-12):1467-76. doi: 10.1016/s0264-410x(00)00347-9.