Appendix XV H (Vet) 1. Healthy Chicken Flocks for the Production of Inactivated Vaccines for Veterinary Use

The risk involved with the use of eggs from healthy chicken flocks has to be assessed in accordance with general chapter 5.2.5. Substances of animal origin for the production of immunological veterinary medicinal products.

Where eggs from healthy chicken flocks are used for the production of inactivated vaccines for veterinary use, the health status of the flock is ensured by means of the system described below.

A flock is defined as a group of chickens sharing a common environment, that have no contact with other poultry flocks of lower health status.

A designated healthy chicken flock is derived from embryonated eggs obtained from healthy flocks or breeder flocks that are of the same health status.

Once the layer flock is defined, no chickens of lower health status may be added. Appropriate measures are taken to prevent or significantly reduce entry of rodents, wild birds or insects and to prevent entry of unauthorised personnel.

Personnel authorised to enter the facility in which the flock is housed must have no contact with birds of lower health status or with agents potentially capable of infecting the flock. It is advisable for personnel to shower and change clothing, or to wear protective clothing before entering the controlled facility.

Wherever possible, it is recommended that the feed is of a quality that reduces the introduction of undesirable micro-organisms as much as possible and that water is at least of potable quality. The flocks may be vaccinated. Live vaccination prior to and during the egg collection period should be avoided where possible, otherwise the associated risks should be carefully considered and the vaccination justified in accordance with general chapter 5.2.5. Substances of animal origin for the production of immunological veterinary medicinal products.

A permanent record of the general health of the flock is kept and any abnormality is investigated. Factors to be monitored include medical treatments (especially vaccinations), morbidity, mortality, general physical condition, feed consumption, daily egg production and egg quality. Records are maintained for a period of at least 5 years. Details of any deviation from normal in these performance parameters are notified to the users of the eggs as soon as possible and within no more than 14 days.

The flocks must be free from Mycoplasma gallisepticum, M. synoviae and from salmonella which is of public health significance or pathogenic for chickens. The flocks are tested before lay and at regular intervals during lay and at the end of egg collection.

The tests or combination of tests must have suitable specificity and sensitivity. Samples are taken for testing from at least 4 different locations, and from 5 animals per thousand, with a minimum of 20 samples.

ROUTINE TESTING OF HEALTHY FLOCKS

Clinical examination is carried out at least once per week throughout the life of the flock in order to verify that the birds are free from signs of any infection. In the event of mortality due to unknown causes during lay, a necropsy is performed on a representative number of available carcasses. Where appropriate, histopathological, microbiological and virological studies are performed to confirm diagnosis.

ACTION TO BE TAKEN IN THE EVENT OF DETECTION OF INFECTIOUS DISEASES

If evidence is found of contamination of the flock, all materials derived from the flock during the 4-week period immediately preceding the date on which the positive diagnosis was made may present a risk of contamination. Any product manufactured with such materials should undergo a risk assessment to determine whether or not they can be used further in vaccine production.

Producers must notify users of all eggs of the evidence of contamination within 14 days of the outbreak.

Any flock in which a clinical outbreak or a positive test is confirmed for M. gallisepticum, M. synoviae or for salmonella which is of public health significance or pathogenic for chickens, cannot be redesignated as a healthy flock.