The old maxim that prevention is better than cure is particularly relevant to dealing with ASF and other TADs. Quarantine is the first line of defence against these diseases. All countries should devote an appropriate level of resources to ensure that they implement effective border and import quarantine policies to prevent the introduction of serious livestock diseases.
Risk analyses for ASF should provide an estimate of:
This should provide the basis for designing and implementing appropriately resourced preventive strategies for ASF.
The most important resource in the prevention of ASF or other livestock disease is the informed animal owner or manager. Pig owners at all levels of production must be able to recognize ASF and know what to do when they suspect it. This can only be achieved by intensive farmer training, using media that are easily understood, highly visual and that will serve as a constant reminder of the disease and its importance. Lines of communication must be established between livestock owners and the veterinary services. Local authorities and agricultural personnel, who must be informed about ASF, should be used as intermediaries when necessary. It has been pointed out that the only people who see animals every day are their owners. Informed owners therefore constitute the only really viable surveillance resource for animal disease.
The OIE International animal health code (1999 edition, Chapter 2.1.12) provides guidelines for the safe importation of domestic and wild pigs, pig meat and meat products, pig semen, embryos and ova and other products incorporating pig tissues, such as pharmaceuticals.
Attention should be paid to providing adequate quarantine services to intercept foodstuffs and other risk materials containing pig meat or products being brought into the country at international airports, seaports and border crossing points. Any confiscated quarantine risk materials should be disposed of safely by deep burial or incineration, as should all food waste from international aircraft and ships.
Swill feeding of food scraps, which may contain imported animal products, is a very important means by which ASF and other serious transboundary animal diseases such as foot-and-mouth disease (FMD), swine vesicular disease and CSF may be introduced into a country. Consideration should therefore be given to placing a ban on swill feeding or at least implementing controls that will make it safe. Every effort should be made to prevent swill feeding of food waste from international aircraft or ships, as this constitutes a high risk for introduction of ASF to new countries. There is a high probability that ASF was introduced into Latin America at least once in this way.
A ban on swill feeding is highly desirable from the point of view of disease prevention. But such a ban would be impossible to monitor at household level, which makes it difficult to achieve in many countries. For many pig producers in rural, peri-urban and urban situations, economic circumstances dictate that any affordable food source should be used. In urban and peri-urban situations where many poor people depend on their pigs for extra income, this food is likely to come from a variety of sources, almost inevitably on a sufficiently informal basis to be beyond the reach of the law. The only possible way to avoid the problem is for pig owners to understand the dangers and to opt voluntarily to boil swill before feeding it to their pigs. Where poverty prevails, the law is usually no deterrent. Awareness of risk and a practical means to overcome it will ensure compliance with regulatory measures. In countries with a developed pig industry, it is possible that farmers will be guided by the law and banning swill feeding might offer protection. It is likely, however, that farmers at the level where the law will be adhered to would not feed swill, because they would appreciate that this type of feeding does not achieve the best results in terms of modern production.
The presence of large numbers of uncontrolled or poorly controlled pigs constitutes a high risk for the entry and rapid spread of ASF. There may be significant delays in recognition of the disease and eradication will be more difficult. Perhaps the greatest danger is that these pigs have access to the carcasses of dead pigs in the bush or on garbage dumps and the offal of pigs that have died of ASF and been prepared for human consumption. Measures should be taken to encourage development of properly constructed pig pens and to reduce the numbers of scavenging pigs, particularly in areas which are considered to be at high risk for entry of ASF. Pig farmer groups at all levels should speed up the process of commercialization, encouraging the establishment of pig-farming organizations. It must be accepted, however, that traditional ways of keeping pigs in many developing countries will not be changed overnight and that permanent confinement of pigs imposes feeding obligations that owners may be unable to meet. The merit of pigs is their ability to convert low-grade feed, including human detritus, into high-quality protein. Until more research has been done on alternative feeds, many producers will not find it worthwhile to confine their pigs. In some countries, sanitation is not readily available and pigs provide a valuable cleansing service. The best that can be hoped for in the short term is that informed pig owners in villages will understand the dangers of disposing of carcasses, offal and remnants of dead pigs on garbage dumps where pigs scavenge. A national policy for upgrading pig production that includes identifying sources of cheap feedstuffs should be put in place.