The Three Levels of Biosecurity
A comprehensive biosecurity program should represent a hierarchy of conceptual, structural, and procedural components directed at preventing infectious disease transmission within and across farms, companies, facilities, regions, countries, and continents. Avoidance is the most effective way to prevent disease transmission involved with animal ownership or production. But given that all movement of animals within or across groups/borders involves risk of contact, biosecurity measures are needed to reduce unavoidable risk.
This primary level of biosecurity revolves around the location of animal facilities and their various components. The most effective way to limit risk is physical isolation, making this a primary consideration when siting new confinement facilities or farms. Facilities/farms should not be located next to public roads, especially when the area has a high density of animal facilities. Similar isolation methods include limiting the use of common vehicles and facilities, limiting access by personnel not directly involved with the operation, and controlling the spread of disease by vermin, wild animals, and wind.
This secondary level of biosecurity deals with physical factors such as farm layout, perimeter fencing, drainage, number/location of changing rooms, and housing design. Long-range planning and programming is important and should consider on-site movement of vehicles, equipment, and animals; traffic patterns; and feed delivery/storage.