Indications for use, specifying the target species
For the active immunization of broiler chickens from 10 days of age with maternally-derived antibodies against avian infectious bursal disease (IBD, Gumboro disease), to reduce mortality, clinical symptoms, weight loss and acute lesions in bursa of Fabricius, caused by very virulent infectious bursal disease virus.
Onset of immunity: 14 days post-vaccination.
Duration of immunity: 27 days post-vaccination.
Do not use in infected flocks with clinical symptoms. Do not use for immunisation of flocks without maternally derived antibodies (MDA) (see Special precautions for use).
Special warnings for each target species
The vaccine contains an “intermediate-plus” virus strain that is known to cause immunosuppression and bursal damage when inoculated into birds without MDA (see sections Special precautions for use, Adverse reactions and Pharmacological particulars). Consequently, the vaccine is only indicated for immunisation of chickens having maternal antibodies and exposed to very virulent IBD virus strains.
Special precautions for use
Special precautions for use in animals
Vaccinate healthy birds only. It is not recommended to vaccinate birds younger than 10 days of age, regardless of the level of maternally derived antibodies (see Amounts to be administered and administration route).
The vaccine contains an “intermediate-plus” virus strain, causing significant immunosuppression and bursal damage when inoculated into birds without MDA. Vaccinated birds may excrete the vaccine virus that may subsequently spread to susceptible birds. To prevent spread of vaccine virus, vaccinating equipment and chicken houses should be disinfected between flocks.
The product should be only used after it has been demonstrated that very virulent IBDV strains are epidemiologically relevant in the area of vaccination.
Vaccinate all the birds in a flock at the same time.
Special precautions to be taken by the person administering the veterinary medicinal product to animals
Personnel performing vaccination should wash and disinfect hands and equipment after use.
Adverse reactions (frequency and seriousness)
Data from safety studies involving administration of a single dose to the target species (10 day old chickens with MDA to IBD virus) are not available. Refer to Overdose section.
Use during pregnancy, lactation or lay
Do not use in layers or breeders.
Interaction with other medicinal products and other forms of interaction
No information is available on the safety and efficacy of this vaccine when used with any other veterinary medicinal product. A decision to use this vaccine before or after any other veterinary medicinal product therefore needs to be made on a case-by-case basis.
Amounts to be administered and administration route
In drinking water use.
Dosage: 1 dose / chicken.
For oral administration, via reconstitution in drinking water. For vaccination of broiler chickens from a minimum of 10 days of age to approximately 18 days of age, depending on the level of maternally derived antibodies.
The optimal timing of vaccination should be determined on the basis of virus neutralisation (VN) titres measured in 1- to 7-day-old chickens. The flock to be vaccinated should have a geometric mean VN titre of <1:450 at vaccination.
To estimate MDA level of the flock to be vaccinated: 20, preferably 1-day-old chicks (maximum 7 day old) originating from the same breeding flock should be sampled to measure their serological status to IBD virus by VN. From the results of this sampling and based on the 3 days half-life-time for the IBD virus MDA, the most suitable time for vaccination can be determined.
Preparation and administration of the vaccine:
The number of vaccine doses should be dissolved in the amount of drinking water calculated upon water consumption of the birds to be immunized.
10 -12 days
14 - 18 days
minimal amount of water for 1000 vaccine doses (for treatment of 1000 birds)
Number of doses should be rounded up for smaller flocks and dissolved accordingly (i.e. dissolve 20,000 doses for the treatment of 19,450 birds).
Drinking water must not contain disinfectants for 48 hours prior to and for 24 hours after vaccination. Also chlorination of drinking water should be avoided during this period. Instruments used for preparation and administration of the vaccine must be free of residues of disinfectants. Drinkers should be cleaned thoroughly before vaccination. Do not apply disinfectants for cleaning of the watering system for vaccination. Drinking water should be withdrawn from birds for 2 to 4 hours prior to vaccination, depending on their age and the temperature of the house. To preserve virus activity, it is advised to dissolve 2.5 g skimmed milk powder per litre of calculated drinking water, prior to dissolving the vaccine.
Open the vaccine vial under water and rinse it thoroughly after dissolution. Stir to dissolve the vaccine, distribute it to watering system proportionally and make it available to the chickens. It is advised to increase the number of drinkers during vaccination. To ensure that all birds have access to the vaccinated water, it is advised to move birds around the drinkers in the first few minutes of vaccination. The birds can be supplied with fresh drinking water only after the medicated water is consumed entirely.
The vaccine should be administered to birds immediately after reconstitution. Administer the vaccine during the coolest part of the day. Protect reconstituted vaccine from direct sunshine. Protect birds to be vaccinated from stress conditions.
Overdose (symptoms, emergency procedures, antidotes), if necessary
From studies involving a 10-fold overdose of Winterfield 2512 L G61 vaccine strain administered to 1-day-old and 7-day-old chickens without maternally derived antibodies (i.e. SPF chickens) the following was noted:
In 1-day-old SPF chickens: lesions of 2.2 scores in the bursa of Fabricius were observed by 28 days post-vaccination as well as a slower growth rate up to three weeks of age. In 7-day-old SPF chickens: clinical signs of infectious bursal disease were not detected. No oedema, haemorrhage or necrosis was detected in the bursa of any chicken by the end of the 21-day observation period.