The role of national registries for human alveolar echinococcosis and long term surveillance of foxes: is early warning possible?
Résumé
In France, the monitoring of human alveolar echinococcosis (AE) is organized by the FrancEchino network, and fox infection surveillance mostly by the Entente de Lutte Interdépartementale contre les Zoonoses (ELIZ). A retrospective analysis of the patient data (1982-2011) indicates that the disease occurs in nested spatial clusters, the geographical position of which varies over time. Furthermore a large scale survey of fox infection, based on necropsy, carried out from 2005 to 2010 in 42 French departments (districts), indicates an extension of the distribution range of the parasite towards West with a prevalence increase in most areas. Often, detection of human AE is the only way to detect new risk areas. However due to the long asymptomatic development of the parasite in human (10-15 years), monitoring fox (and/or dog) populations should be a better way to anticipate risks for human exposure. However fox sampling is logistically difficult at the relevant scales and time frequency and seldom an option for a rare disease in Europe. A new quantitative PCR that we developed to detect more efficiently E. multilocularis in carnivore faeces may overcome this problem and be used for large scale as well as fine spatial resolution studies.