Review/Oorsig Volume 23, Issue 02 - Page 10

Oorsig/Review As far as the Eurasian lineage is concerned, the clear finding is that no wildlife species – including African buffalo – is able to maintain either of the FMD virus lineages for any significant length of time, although some may become infected. There is also no evidence that antelope, for example, in Southern Africa can maintain SAT viruses for significant periods of time; buffalo provide a constant source of infection for other cloven- hoofed wildlife. Maintenance of SAT viruses by cattle It has traditionally been assumed that, as is the situation for impala in the Kruger National Park, for example, all or at least most FMD outbreaks in cattle in Southern Africa are derived from contact with buffalo. This is unlike the situation in East Africa where SAT viruses in circulation in cattle and those in African buffalo have so far been found to be independent of each other. There is increasing evidence that cattle in Southern Africa may maintain some specific strains of SAT virus (SAT 2 and 3 especially) for many months or even years independent of buffalo and that many if not most of these infections do not result in disease. This makes the Fig 3. Long-term FMD control in Southern Africa since 1931 10 detection of FMD in cattle unreliable by physical inspection alone. If this suspicion turns out to be correct it will make the management of FMD in this part of the world even more complicated than it already is. Control of FMD in Southern Africa The occurrence of SAT-type FMD outbreaks in cattle in Southern Africa – especially since the turn of the 21st Century – has increased considerably, despite the best efforts of the official veterinary services of the region (Fig. 3). The reasons for that have not been established conclusively but the hard fact is that since about 2000 the FMD situation in the region has deteriorated. Essentially there are two broad possible reasons: (1) the conventional approach which has been adopted for close to half a century – based primarily on fencing to control animal movement and mass vaccination – has not been applied as effectively as formerly and/or (2) the traditional approach is no longer appropriate for the evolving FMD situation in the region. The latter reason is probably at least partly the case and therefore a fundamental reassessment of FMD control strategies in Southern Africa is overdue.