The strategies discussed in Chapter 6 were based on the premise that an emergency disease outbreak has been detected relatively early and is still only present in one or a few discrete areas. Countries that are not in this fortunate position and contend with endemic FMD should strategically consider whether a national disease eradication campaign is practical. The spreading of resources too thinly over too large an area may result in setbacks and frustrations all round.
It may well be more effective to tackle control and eventual eradication by vaccination in a step-by-step progression, moving from one region to the next. In this case, regions should be defined and selected on the basis that once eradication has been achieved in a region, and the campaign moves on to the next, there can be confidence that the first region is "secured" and that the disease will not re-enter. Geographic barriers should be utilized wherever possible. In this respect, archipelago countries are fortunate in that eradication can be done as an "island hopping" campaign. Otherwise use should be made of any epidemiological or livestock production and marketing patterns that tend to make an area a discrete unit in terms of disease spread.
Next is the question of prioritization for each region. There is merit in selecting the major livestock breeding areas in the country first, since these have the most to lose and, if infected, pose the greatest risk of further spread. Because of the number of animals involved, these areas may be important sources for the virus to appear in other parts of the country. Another advantage of tackling these areas first is that, when FMD-free, they will act as a valuable source of disease-free animals for restocking other areas.
Further prioritization should also be based on an understanding of epidemiological factors and livestock production and marketing systems, which influence how and where the disease spreads. Where FMD strikes is a reflection of how unprotected animals have encountered the virus from other animals or the environment, but the location may not be the origin of the virus. Often it may be more efficient to vaccinate animals "upstream" where the virus is present in its ecological niche, rather than wait for the virus to enter a large susceptible population "downstream". Livestock movements and direct contact between animals are often overwhelmingly the most significant transmission of FMD. Therefore, a thorough understanding of livestock movement patterns and routes is often vital for effective prioritization within FMD eradication campaigns.
Vaccination should also be timed appropriately, taking into consideration seasonal animal husbandry and livestock movement patterns. Animals should be vaccinated at times of the year before movements are likely to occur, e.g. before dispersal of young stock and movement of animals to fresh pastures.
These incremental programmes for the progressive development of FMD-free zones by vaccination should be supported by strong disease surveillance programmes that monitor the effectiveness of the campaign, and also by livestock movement controls that will prevent the reinfection of areas freed of the disease.
Where eradication is the goal, vaccination should not be allowed to become just a routine activity that is maintained almost indefinitely because of fear of political consequences if it ceases and another outbreak subsequently occurs. When the clinical disease appears to have disappeared from either a region of a country or the whole country it is time to take stock of the situation and carry out a thorough epidemiological and economic assessment of future options.
It may well prove desirable to maintain strategic vaccination if there is still a very high risk of a new incursion of the disease from a neighbouring country. On the other hand, in many cases it is advantageous to change the course of action completely by stopping vaccination programmes altogether and moving to a disease "search and destroy" policy. This does not necessarily mean that fewer resources will be devoted to eradicating the disease in the short term. Rather they will be directed away from routine vaccination to increased early warning and early response activities. There must be willingness to enhance active disease surveillance activities and maintain preparedness against the disease at a high level. In this way, any disease breakdowns can be detected and eliminated quickly by either a short, sharp, targeted vaccination campaign or by limited stamping out.
