- F X Meslin: Division des Maladies émergentes et autres Maladies transmissibles, Surveillance et Lutte, Organisation Mondiale de la Santé, Genève, Suisse.
Emerging or re-emerging zoonoses is a relatively complex topic. The concept covers not only new or recently identified zoonotic agents but also agents that are already known but appear in regions and/or species in which they have not been previously observed and agents that disappear then reappear in a country in the form of an epidemic outbreak. Many wild or domestic species and almost all infectious agents may be involved. In general intervention either by vaccination or by elimination of suspect or contaminated individuals is easier in domestic animals than in wild animals especially since the latter may belong to an endanger species. Because of the wide range of pathogenic agents, animal vectors and target populations, there are a wide variety of epidemiological patterns and adapted surveillance and control strategies must be used with various degrees of success.