francesco prandini
TRANSCRIPT
Francesco Prandini – DVM MERIAL Avian Technical Manager EMEA
Protection against Salmonella infection
using vaccines
Baromfiágazat annual Seminar 2013
Budapest, October 1st 2013
Introduction
• Salmonella spp is one of the major causes of food-borne illness in humans
• High prevalence of Salmonella in poultry
• Chicken and chicken products are the most frequent sources of zoonoses
World Poultry - Dec 29, 2011
Salmonella
• Motile non-host-specific serovars:>2000 serovars nearly ubiquitous in wild and
domestic animals
• Very common but seldom cause clinical
disease
• More often, asymptomatic persistent
colonization of the intestinal tract
• “Paratyphoid” infections of
poultry and zoonoses
Zoonoses cases in humans in 2011
Salmonella epidemiology• S.Enteritidis (SE) and S.Typhimurium (ST)
are the serovars most frequently associated with salmonellosis in humans through the food chain
• Commonly asymptomatic colonization of chickens in the intestinal tract
• Egg shell contamination
• SE can infect eggs internally
Distribution of food vehicles in outbreaks caused by S.Enteritidis in the EU, 2011
Distribution of the 10 most common Salmonella serovars in humans in the EU, 2010-2011
Salmonella in human cases, eggs and laying hens and the number of Salmonella outbreaks caused
by eggs within the EU, 2007-2011
BreedersGallus gallus
Laying hensGallus gallus
Broilers Turkeys
S.Enteritidis S.Enteritidis S.Enteritidis S.Enteritidis
S.Typhimurium S.Typhimurium S.Typhimurium S.Typhimurium
S.Infantis
*All salmonella serovars with public health significanceS.Hadar
S.Virchow
Serovars* with established targets for reduction of prevalence in the EU
Salmonella control in Chickens• Control of biological reservoirs:
– Breeders– Replacement flocks– Rodents– Red mites
• Rigorous biosecurity measures• Slaughtering of positive Breeders/Layers flocks• Competitive exclusion and Probiotic effects• Vaccination• Comprehensive programs of risk reduction
Salmonella VACCINATION
Specific protection against S. serovars
Both Live and Killed vaccines have been associated with significant protection
An important component of SE-ST plans of risk reduction in Layers and Breeders
Farm-tailored vaccination strategies
Salmonella VACCINES
Live attenuated vaccines:• Mass application
• Mainly local immune response
Inactivated vaccines:• Individual s.c./i.m. injection
• Mainly humoral immune response
Vaccination programs:• Live
• Inactivated
• Live + Inactivated
Live VACCINE
A live attenuated vaccine against S. Enteritidis Adenine - Histidine double auxotrophic strain Drinking water administration 2 or 3 doses tailored programs Early and long-lasting protection Easy and rapid field strains differentiation
Gallivac Se strain Field strain
Challenge trial with GALLIVACChallenge trial with GALLIVAC SeSeOral Vaccination @ 2,16 & 114 days of age, and challenge with 5 billion pathogenic SE bacteria into the crop of each bird at 78 weeks of age.
Number of bacteria per gram of tissue 7 days after challenge.
0
10.000.000
20.000.000
30.000.000
40.000.000
Caecum @ 79 weeks
Un vaccinated Gallivac Se
0
50
100
150
200
250
300
Liver at 79 weeks
Inactivated VACCINE
A bivalent inactivated vaccine against S.Enteritidis and S.Typhimurium for pullets
Innovative manufacturing method to preserve antigenicity
0.3 ml emulsion dose s.c. or i.m. 2 doses program: from 6 wks & 16 wks Rapid and lasting protection
Classical processControlled nutrient fermentation
Blood sampling
Comparison of inactivated vaccines
Gallimune® Se+St
W10
W16
W16
W10
W30
Se+St Al hydroxide
W16W10
Control group unvaccinated
W30
W30
G 1
G 2
G 3
Antibody titres at 30 weeks
Gallimune® Se+St
W10
Competitor vaccine
W16
W16
W12
Challenge
W27
W27 +4 days
+4 days
Ovary sampling
60 pulletsSE PT4 oral challenge
Challenge 1: ovary contamination
Challenge trial with Gallimune® Se + St
Results of isolation of S. Enteritidis PT4 in the ovaries of birds 4 days post oral challenge at 27 weeks of age.
-90%
• Groups of 60 pullets:– Vaccinated at 10 & 16 weeks of age with
Gallimune Se + St - 0.3 ml
– 12 & 16 weeks with reference vaccine - 0.5 ml
– Controls
– 29 weeks of age: oral challenge with ST
– 31 weeks of age: oral challenge with SE
– Caecal droppings collected 4 days post challenge
Challenge trial with Gallimune® Se + St
Gallimune®
Se+St
W10
W16
W16
W12
W29
W29
+4 days
Challenge 2: fecal shedding
Other vaccine
• 29 weeks ST challenge oral route• 31 weeks SE challenge oral route
+4 days
Gallimune® Se+St
Reference vaccine
Challenge Faeces sampling
Challenge 2: fecal shedding
Challenge 2: fecal shedding
SINGLE or COMBO vaccination programsPROTOCOL
Age of chicks Group 1 Group 2 Group 3
Day 1Gallivac Se
drinking waterGallivac Se
drinking waterControls
Day 42Gallivac Se
drinking waterGallivac Se
drinking water ---
Week12Gallivac Se in
drinking water --- ---
Week 4 Gallimune Se+St
im breastinjection
---
Week 52 challenge with
SE or STchallenge with
SE or STchallenge with
SE or ST
Challenge study PROTOCOL
• Lohmann Brown Commercial layers
• Oral challenge with 109 CFU of SE or ST
• Birds sacrificed 7 days after challenge
• Enumeration of SE and ST cells per g. of caecal content
52 weeks - SE challenge
52 weeks - ST challenge
Conclusions Salmonella requires comprehensive control plans
Vaccination is an important component
Live and inactivated vaccines has specific features
Combined vaccination programs consolidate advantages from both
Farm-tailored vaccination strategies are required
Thanks for your attention