Morand S. auteur aut IRD Guégan Jean-François auteur aut IRD text journalArticle eng text/pdf reformatted digital access Although the term endemism refers to restricted areas of taxa, this term is used in a different way in epidemiology and host-parasite relationship. An endemic disease refers to the maintenance of a disease over a long-term period in a limited geographic area (endemic area). In biogeographical studies, endemism refers to the organisms that are restricted to a given area. However, little is known about parasitism in endemic hosts. Here, we show how epidemiological models and the derivation of the basic transmission rate (R0) can help to understand the pattern of parasite species richness among endemic hosts. The main prediction arising from epidemiological models concerns the host density threshold, i.e. the minimum host density that allows a disease to spread into a population of susceptible hosts. When host density, or host range, increases we can predict a concomitant increase of parasite species richness, in the case of parasites transmitted directly or through predator-prey relationship. This prediction can be tested using comparative data. These predictions are successfully tested using several data sets on parasites of marine and freshwater fish. We will show that restricted areas and/or low density is correlated with a decrease in parasite species richness. The epidemiological theory is also helpful for predictions concerning parasite and disease introductions in endemic host faunas (or isolated hosts). We emphasize why and how this endemic fauna may be susceptible to introduce pathogens and parasites. (Résumé d'auteur) specialized PARASITISME ESPECE ENDEMIQUE RELATION HOTE PARASITE TRANSMISSION VECTEUR DENSITE DE POPULATION DIVERSITE SPECIFIQUE EPIDEMIOLOGIE MODELE MATHEMATIQUE POISSON MARIN DYNAMIQUE DE POPULATION REPARTITION GEOGRAPHIQUE HABITAT BIOGEOGRAPHIE IMMUNITE ETUDE COMPARATIVE AMERIQUE DU NORD 080ZOOGEN03 2 135-147 2000 1374-5514 https://www.documentation.ird.fr/hor/fdi:010023454 1374-5514 [F B010023454] https://www.documentation.ird.fr/hor/fdi:010023454 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_7/b_fdi_55-56/010023454.pdf IRD - Base Horizon / Pleins textes 2000-12-08 2018-07-10 fdi:010023454 fre