Assessing risks of disease transmission between wildlife and livestock : the Saiga antelope as a case study

Disease transmission between wildlife and livestock can undermine conservation efforts, either by challenging the viability of threatened populations, or by eroding public tolerance of actual or potential wildlife disease reservoirs. This paper describes the use of transmission models to assess the risk of disease transfer across the wildlife-livestock boundary, and to target control strategies appropriately. We focus on pathogens of the Saiga antelope (Saiga tatarica) and domestic ruminants in Central Asia. For both foot and mouth disease and gastrointestinal nematodes, the main risk is associated with infection of saigas from livestock, and subsequent geographical dissemination of infection through saiga migration. The chance of this occurring for foot and mouth disease is predicted to be highly dependent on saiga population size and on the time of viral introduction. For nematodes, the level of risk and predicted direction of transmission are affected by key parasite life history traits, such that prolonged off-host survival of Marshallagia in autumn enables infection of saigas and transfer northwards in spring. Field estimates of parasite abundance provide qualitative support for model predictions. The application of models as tools for the early evaluation of disease transmission between wildlife and livestock is discussed. (c) 2006 Elsevier Ltd. All rights reserved