Logistical and biosecurity issues associated with disease control at a farm-level

When planning and performing an infectious disease control operation, the aim is to contain the pathogen within the affected premises and prevent further transmission. The classification of the biological agent, number of other susceptible animals in the area and way in which the disease is transmitted (vectors, direct contact, airborne etc.) will determine how quickly the animals should be killed. For example, there would be more urgency in the case of Foot and Mouth Disease (FMD) than of BSE. The elimination of infectious disease from an infected area must be performed in a timely and effective manner. As live animals present a major risk of spreading infectious pathogens they need to be killed quickly and humanely.

As stated previously, at national level a Contingency Plan must be established to control the spread of disease between premises across the country. Local and farm-level Biosecurity Plans must also be written by farmers and stockowners, describing the protocols in place on their own farm. Some governments offer guidance on the development of farm Biosecurity Plans on their websites. A Biosecurity Plan must include means of securing the premises and preventing the escape of the agent on animals, animal products, clothing or equipment or through environmental factors (e.g. wind). The division of “clean” (pathogen free) and “dirty” (infected) areas on a farm must be clearly marked to avoid accidental contamination by people moving between sites. Disinfectant should be provided and all personnel instructed in the efficient application of steriliser to themselves, equipment and vehicles. All team members and visitors to the farm must adhere to these rules. When planning the positioning of killing areas and fallen stock pick-up points, the contamination risks from the vehicles have to be taken into account. These areas should be positioned close to farm entrances to minimise vehicle movement on the premises. It is also important to devise a system so that animals are moved in only one direction and do not pass through killing or fallen stock areas before it is time for them to be killed and removed from the farm. As vehicle and equipment movement is one of the biggest contributors of disease spread, parking areas for visitors (e.g. vets, killing personnel etc.) should be provided. If possible, it is recommended this is situated off site to prevent contamination from people and vehicles. These areas should be clearly identified on the farmer’s Contingency Plan. If necessary, a dedicated vehicle should be arranged to bring personnel to infected premises from a dedicated meeting point. There should be facilities for the washing and disinfecting of people’s clothing and vehicles to prevent spread between and within farms. If possible, visitors should limit their movements and only enter/exit using one route. Additional fencing around the farm can help to prevent disease transfer between the site and neighbouring farms. These fences can also stop wildlife, such as badgers and foxes, from entering the premises and spreading the disease further, or feeding on fallen stock.  See Figure 3 below for an example for a farm layout.

Figure 3: Diagram showing possible farm layout with consideration given to needs relating to animal and vehicle movement while maximising biosecurity provisions. 

Next: Human safety