francesco prandini

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