The Wildlife Domestic Animal Disease Interface—should Africa adopt a hard or soft edge?

Abstract

Diseases at the interface between livestock and wild animals have been observed and studied for many decades but recently there has been an upsurge in interest with improvement in our understanding of the epidemiology of multi-host infections and better diagnostic tools.

Recognition of the problem of disease at the interface has led to landscape management to reduce the risks of transmission and associated production losses and to enhance access to markets. These markets pay a premium on food safety and disease freedom in producer herds, and are situated in countries, which have largely controlled the major epizootic diseases. The main approach to control or prevention of transmission at the interface is through the so-called hard edge where contact between livestock and wild animals is minimized through strict land use policies and fencing to restrict animal movement. This approach has been successful but only with strong economies where there has been sufficient investment. The other more passive management is the so-called soft edge, where a more integrated system prevails with livestock and wildlife sharing land and resources. This is the situation in most of Africa, where there are predominantly pastoral or nomadic systems, which cross national boundaries. These systems are recognized as being sustainable in the long term and most efficient in the more arid lands of the continent. However, it is becoming increasingly clear that under these conditions conventional disease control measures are impractical and perhaps unnecessary (with some diseases), as these endemic diseases have little economic impact. There is however an opportunity loss associated with the lack of access for pastoralists to the lucrative export trade due to current phyto-sanitary trade rules but it is questionable if these particular animals will ever easily be acceptable on product quality alone.

Whatever the local issues, these interface diseases will remain a concern, as the potential for spread has been enhanced by the “global highway”, which allows rapid movement of animals, people and products across the continents and these are discussed in the paper. Finally, the current and future role of the veterinary profession in this field is considered. Vets have to some extent lost the initiative in Africa on disease, with an obsessive promotion of out of date dogma on specific animal health issues, and with a tendency for the schools to promote “Western” curricula more appropriate to developed societies, with emphasis on high production livestock systems, horses, dogs, cats and exotic pets.