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Cross-protection of RESPIPORC FLU3GRIPOVAC 3 against swine

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					Cross-protection of RESPIPORC® FLU3/GRIPOVAC® 3 against swine flu: challenge trials with
                           two recent European H1N1 strains
                    Ralf Dürrwald1, Michael Schlegel1, Hans-Joachim Selbitz1, Thaïs Vila2
                  1IDT Biologika GmbH, Dessau-Rosslau, Germany, 2Merial S.A.S., Lyon, France
                                     ralf.duerrrwald@idt-biologika.de

Introduction                                                      Figure 1: Mean viral load (EID50 in 10 mg lung
Swine influenza viruses of three different                        tissue) after aerosol challenge with strain RA
subtypes, H1N1, H3N2 and H1N2 are now co-
circulating in European countries (1). The
commercial vaccine based on H1N1 and H3N2
strains doesn’t protect against H1N2 infection (2).
A new swine influenza vaccine RESPIPORC®
FLU3/ GRIPOVAC 3 adapted to European
epidemiology contains H1N1, H3N2 and H1N2
recently isolated strains. The objective of this study
was to evidence the cross-protection of this vaccine
against recent H1N1 strains isolated in France.
                                                                  Day 1: p=0.026; Day 3: p=0.021
Material and Methods
H1N1 strains from two different genotypes of                      Figure 2: Mean viral load (EID50 in 10 mg lung
swine influenza viruses isolated in Brittany                      tissue) after aerosol challenge with strain AL
(France) were used in this study: A/sw/Cotes
d'Armor/0190/06 (reassortant H1N1=RA) and
A/sw/Morbihan/0070/05 (avian-like H1N1=AL)
(3). The antigenic character of these strains was
investigated by cross-neutralisation with specific
hyper immune sera of pigs (Kuntz-Simon et al., in
preparation). They were kindly provided by G.
Kuntz-Simon, AFSSA-LERAPP, F-Ploufragan.
Pig vaccination: All 49 experimental pigs were
seronegative against H1N1, H1N2 and H3N2 prior
to vaccination. Half of the pigs (N=24) were                      Day 1 and Day 3: p=0.008
vaccinated with 2ml RESPIPORC FLU3/
GRIPOVAC 3, IM twice, 3 weeks apart. The other                    Conclusion
half was injected with a placebo.                                 These experiments with heterologous swine
Challenge: One week after 2nd administration of                   influenza viruses challenge clearly show the cross-
2.0 ml of the vaccine, an aerosol challenge                       protection of the vaccine strains of RESPIPORC
validated in previous studies was conducted.                      FLU3/ GRIPOVAC 3 with recent H1N1 Swine
Viral load in lung tissue homogenates was                         Influenza A field strains from Europe.
quantified by egg culture and expressed in number
of egg infection dose 50% (EID50).                                References
                                                                  1. Kuntz-Simon G. et al., (2009) Zoonoses and
Results and Discussion                                            Public Health, 56, 310-325
The challenge strain RA did not induce clinical                   2. Van Reeth K. et al., (2003) Veterinary Record,
signs of the disease (neither dyspnoea nor fever).                153,9-13
Vaccinated pigs had significantly lower viral lung                3. Franck N. et al., (2007) Proc. 5th Int. Symp. on
load than not vaccinated pigs both 1 and 3 days                   Emerging and Re-emerging Diseases in pigs,
after challenge.                                                  Krakow, Poland, p. 250
The challenge strain AL did induce only mild
clinical signs of disease (mild dyspnoea but no                   ® RESPIPORC is a registered trademark of IDT.
fever), consequently no difference was observed                   GRIPOVAC is a registered trademark of Merial
between treatment groups.                                         S.A.S.
Vaccinated pigs had a highly significantly lower
viral lung load than not vaccinated pigs (no virus
in the lungs of the vaccinated pigs) both 1 and 3
days after challenge.

                         21st International Pig Veterinary Society congress, Vancouver, Canada, 2010

				
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posted:1/6/2013
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