Four crucial steps may be distinguished in prevention and control, all of which are important in order to limit as far as possible the damage resulting from an African swine fever outbreak.
Prevent an introduction
Introduction can only be prevented by being careful with infected animals and products from abroad. The significant measures for this are:
- No import of live animals, meat and meat products from regions where African swine fever occurs. Also bear in mind the meat products that are brought in from affected regions by individuals, for example by truck drivers on long routes, commuting foreign workers, hunters hunting abroad and tourists.
- Ban on swill feeding and being alert to exposing pigs and wild boar ‘by accident' to possibly infected food products (a salami sandwich discarded carelessly outdoors or at a petting zoo, or wild boar with access to kitchen waste via refuse bins or refuse heaps). Pig farmers must also be on the alert for visitors bringing food onto their farms.
- Cleaning and disinfection of livestock transports returning from abroad.
- Cleaning and disinfection of materials used when hunting in or in the vicinity of infected areas.
Limit further spreading
Introduction of the virus will initially always go unnoticed. Presumably there will be a few weeks between the time of introduction and the first diagnosis. During this phase the virus will be able to spread unchecked to other farms. Measures will be needed to limit this as far as possible under all circumstances:
- Restrict the number of contacts between pig farms. This applies primarily to contact between animals, but also to indirect contacts, such as interpersonal contact and to contact via manure, trucks and other materials.
- Ensure that essential contact is rendered safer by (mandatory) hygiene precautions.
Trace a possible infection early
In order to control an infectious disease like African swine fever at source, rapid tracing of a new outbreak is essential. Pig farmers bear great responsibility. They see their pigs daily and will be the first to observe suspected symptoms. In this regard, it is essential that the right follow-up steps are taken quickly to confirm the disease in the laboratory or to rule it out.
Treatment of the disease is not possible. If an outbreak occurs, the disease will initially have to be controlled using zoosanitary measures:
- Culling animals on infected farms, followed by cleaning and disinfection
- Tracing possible contact farms, followed by quarantine or preventive culling
- Tightening biosecurity measures
- Transport ban on pigs and pork products
- Improving surveillance in the region where the outbreak occurred.
Preventive culling depends on the situation
As the African swine fever virus spreads much less readily via indirect contact than does for instance classical swine fever virus, the extent to which preventive culling may be effective or justified is unclear. Based on circumstantial evidence, preventive culling related to neighbourhood contacts (undetermined contacts within a radius of e.g. 500 or 1000 meters around an infected herd) is likely to be ineffective and therefore difficult to justify. Preventive culling in other situations may depend on the specific circumstances of the actual contact with the infected herd.
Vaccination not possible
No vaccine against African swine fever is available.