Frequently Asked Questions Nobilis® Salenvac and Nobilis® Salenvac T

What is Nobilis® Salenvac and Nobilis® Salenvac T?
Nobilis® Salenvac T is an inactivated vaccine containing Salmonella Enteritidis ‘phage type 4 and Salmonella Typhimurium DT 104.

Nobilis® Salenvac contains Salmonella Enteritidis phage type 4.

Is ‘phage type or DT important in the way the vaccine works?
Merck Animal Health simply used the most common types affecting chickens in Europe. The designation ‘phage type 4’ refers to the way in which a particular set of bacteriophages attacks the Salmonella and is used to help researchers find the source of outbreaks. Definitive Type (DT) is a way of sub-dividing S. Typhimurium. As far as efficacy is concerned, the vaccine acts equally well against all strains of S.Enteritidis and S.Typhimurium.

Does Nobilis® Salenvac T cross-protect against any other Salmonella?
Research in the UK shows that Salenvac T gives group protection. For example S. Typhimurium belongs to Group B and trials have shown the control of other group B serotypes - notably S. Agona and S. Heidelberg (international dossier).

What are IRP's?
IRP stands for Iron Regulated Proteins in the outer membrane. These are special, highly antigenic proteins expressed on the surface of the Salmonella cell during growth in the bird's intestine where there is a shortage of iron. Merck Animal Health mimics this situation when preparing the vaccine and the final vaccine is almost identical in relation to antigenic composition to the Salmonella that would challenge the bird. The bird produces antibodies that are exactly the ones needed to combat this challenge.

For more information see Iron Restriction Technology

What sort of immunity does Salenvac T give?
Two injections of Salenvac T give an immune response consisting of Immunoglobulins G (IgG) and M (IgM) as well as cell-mediated immunity. IgG is also excreted in the bile. This means that Salenvac T controls the Salmonella challenge in both the intestines and the organs.

Is immunity provided by Nobilis Salenvac found in the egg?
Immunoglobulins are concentrated in the egg. For eggs that will hatch to become broiler chickens, this means that chicks are protected for at least 21 days against S. Enteritidis challenge (UK research using Salenvac 1995). In relation to eggs for human consumption, this means that eggs are very unlikely to be laid with Salmonella in them. Recent research has shown that if they are contaminated with S. Enteritidis after laying, the bacteria cannot grow well and the numbers of S. Enteritidis remain low in comparison with unvaccinated control eggs.

How successful has Nobilis® Salenvac been in the UK?
Nobilis® Salenvac (S. Enteritidis only) was launched in 1995 and when used in laying birds from 1997 to 2001 was responsible for a 63% reduction in human food poisoning cases from S. Enteritidis. A UK government organisation (The ACMSF) said Salmonella control was ‘a real success story’ and attributed much of this to vaccination. Salenvac was the only available vaccine at the time.

When should birds be vaccinated with Nobilis® Salenvac or or Nobilis® Salenvac T?
The first vaccination is usually at 12 weeks of age and the second at 16 weeks. Two vaccinations are needed to give full immunity, and should be at least 4 weeks apart. So you can use the vaccine at the most practical time. In high risk areas it is possible to give at day old 0,1 ml with a repeated dose 4 weeks later (0,5 ml). Recommended is to give a booster dose at 18 weeks.

Where should Nobilis® Salenvac or Nobilis® Salenvac T be administered?
Both Nobilis® Salenvac and Nobilis® Salenvac T should be administered intramuscularly under aseptic circumstances.

What adjuvant does Nobilis Salenvac T contain?
Alhydrogel - Aluminium Hydroxide Gel. This is a water-soluble adjuvant that minimizes vaccine reactions and is safer in case of accidental self injection than water in oil Salmonella vaccines.

Why is Nobilis® Salenvac T, as used, more effective than a ‘drinking-water-only’ vaccine?
When a Salmonella vaccine is injected it results in the production of antibodies which prevent the ovaries being infected. This avoids vertical transmission of Salmonella through eggs. Control of vertical transmission is the key to successful control of S. Enteritidis. Drinking-water-only vaccination merely causes a local intestinal immunity which controls shedding of the Salmonella but not vertical transmission by birds with infected ovaries.

Are there any other benefits from vaccination with Nobilis Salenvac T?
Trials with Nobilis® Salenvac showed that there was an increase in productivity in broiler breeders following vaccination. In two trials the number of chicks per vaccinated breeder rose by 2.15 and 1.91 respectively and the cumulative hatchability rose by 2.64% in one trial.

Is it true that Nobilis® Salenvac or Nobilis® Salenvac T adversely affects the birds after vaccination?
Handling and injecting birds with Nobilis® Salenvac and Nobilis® Salenvac T gives only a minimal vaccine reaction. This means no disruption in growth and onset of production

What other avian species has Salenvac T been used for?
Salenvac T has been used (off label) in turkeys (2x0.5ml injections 4 weeks apart), ducks (2x0.5ml injections 4 weeks apart) and pigeons (2x0.1ml injections 2 weeks apart).

For the use of the vaccine in turkeys please refer to the following publication Tenk I., Gyorváry I., Erdei P., Szabó Z., Kostyák Á. and Mátray D. (2000)
Effect of a vaccine against Salmonella enteritidis (Salenvac) on salmonella shedding in breeder turkey flocks.
Hungarian Veterinary Journal 122:737-741
See Publications for english abstract

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