Issue |
Vet. Res.
Volume 39, Number 3, May-June 2008
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Number of page(s) | 16 | |
DOI | https://doi.org/10.1051/vetres:2008001 | |
Published online | 15 February 2008 | |
How to cite this article | Vet. Res. (2008) 39:26 |
DOI: 10.1051/vetres:2008001
Intramuscular vaccination of young calves with a Salmonella Dublin metabolic-drift mutant provides superior protection to oral delivery
Tetsuo Mizuno, Malcolm McLennan and Darren TrottSchool of Veterinary Science, The University of Queensland, Brisbane, Queensland, 4072, Australia
(Received 5 June 2007; accepted 17 December 2007; published online 15 February 2008)
Abstract - In homologous and heterologous challenge trials using
calves 6 weeks old, this comparative
study investigated safety, in vivo behaviour and protective properties of
oral and intramuscular vaccination
with recently developed live attenuated Salmonella Dublin mutant N-RM25. Neither oral
nor intramuscular
vaccination produced unacceptable side effects. However, the vaccine strain
was isolated for up to eight
days from the faeces of orally vaccinated calves, but not intramuscularly
vaccinated calves. Irrespective of
the vaccination route, N-RM25 was isolated in low numbers (
1
102 cfu/g) from the liver and spleen
of calves euthanized at different time points post-vaccination. Vaccination
by either route significantly
reduced clinical signs and faecal shedding, prevented the development of
systemic infection and protected
calves from homologous lethal challenge conducted within 14 days
post-immunisation. No challenge strain
was isolated from major organs and the gut at 18 days post-challenge (except
for a single mesenteric
lymph node (MLN) specimen from the intramuscular group, but only following
enrichment). Following
heterologous challenge with a virulent Salmonella Typhimurium strain at 14 and 20 days
post-immunisation,
all vaccinated animals exhibited significantly fewer clinical signs and
colonisation of the intestinal tract
than non-vaccinated controls. When compared to oral vaccination,
intramuscular vaccination significantly
reduced the frequency of faecal shedding of S. Typhimurium (p = 0.0023) and
markedly reduced
colonisation ofMLN. The findings indicate that intramuscular administration
of N-RM25 was safer in terms
of environmental contamination by the vaccine and provided better early
onset protection in young calves
following both homologous and heterologous challenge.
Key words: Salmonella Dublin / metabolic-drift mutant / live attenuated vaccine / early onset protection / calf
Corresponding author: t.mizuno@uq.edu.au
© INRA, EDP Sciences 2008