Epidemiological surveillance of infectious diseases in France.

Epidemiological surveillance, namely the continuous monitoring of diseases and health determinants in a population, has developed over the past fifteen years, in the sphere of human health as well as in animal health. All epidemiological surveillance networks include the following four stages: data collection, data transmission, data processing and dissemination of information. However, despite this basic similarity, the very many networks existing in France are extremely varied in nature. At the national level, the bodies involved in epidemiological surveillance for infectious animal diseases are the Direction générale de l'alimentation, the Agence française de sécurité sanitaire des aliments and, to a lesser degree, the Institut français de recherche pour l'exploitation de la mer. In the field, the networks rely on the Direction des services vétérinaires, veterinary practitioners, laboratories in each département, and livestock producers' groups (especially animal health protection groups). Some twenty French networks currently in operation are presented in this article according to a classification based on published criteria. In the case of human infectious diseases, epidemiological surveillance is carried out almost entirely by the Direction générale de la santé and the Directions départementales d'action sanitaire et sociale, the Institut de veille sanitaire and the various Centres nationaux de référence (CNRs). Most human infectious diseases are monitored by one or more of the following broad categories of networks: reporting of notifiable diseases, the CNRs, the network of sentinel doctors, the network of hospital laboratories and departments, and medical causes of death. An example where surveillance is covered by several networks is also presented, namely surveillance for salmonellosis and Salmonella. Lastly, methods for evaluating networks are discussed.