An important element of prevention, which has a great impact on the effectiveness of anti-epizootic protection of farms, is to create the conditions for introducing the “black and white” system in them. It consists of dividing the tightly fenced area of the farm into a “white” production zone and a “black” supply and administration zone.
The “white” zone should include only that part of the farm where the animal buildings are situated. This zone must be isolated as far as possible from the surroundings. To this end, it should be separated from the “black” area by a solid fence. Entry to this zone must be limited to the necessary number of people, and equipment and other materials may only be brought in and used after they have been decontaminated. Entry of persons into the white zone should be restricted to authorised persons only, i.e. farm staff, veterinarians and the farm owner.
Entry to the clean area takes place exclusively through the so-called personnel locks located on the border of the “white” and “black” areas. In these sluices there is a change of outer clothing (sometimes even a bath) and shoes previously washed and disinfected, and disinfection of hands. Food should only be consumed in special communal areas. The ‘black’ area, which usually houses feed silos and other equipment and buildings used for supply and administration, is necessarily in direct contact with the environment and should therefore be considered an epizootiologically insecure part of the farm. In the gate leading to this area, there should be a covered basin for decontaminating vehicle wheels, equipment for washing and disinfecting bodies, and an area for decontaminating footwear and hands of people entering. This zone is intended to act as a pre-epizootic filter, limiting the possibility of germs entering the production part of the farm. The main entrance to the “black” area should be kept closed at all times. Every person and vehicle entering the farm should be registered and, above all, drive or pass through the disinfection mat.