Acarological data for the eco-epidemiologic study of Lyme borreliosis: Ixodes ricinus Linne, 1758 populations in South Western France

摘要

In Order to understand how Lyme borreliosis foci are generated on the French territory, a complete picture of the true distribution of the tick vector Ixodes ricinus is required. A set of fundamental data was acquired through a method using plant communities as indicators. The results presented in this article are related to the South-Western quadrant of France. The study area includes the following regions: Landes, Bassin Aquitain, the foot-hills of the Pyrenees and the western part of Massif Central. The aim of the study was to ascertain the presence of the vector in the various parts of a territory of great ecological variety. A zoning was first carried out in order to define phyto-ecological and geographical units. Seventeen units were delineated. In a range of 5 to 10 forest experimental sites per unit, the flagging method was used for one hour s time to take samples of the tick during its period of activity. Ixodes ricinus was found in all the phytoecological zones, except three. Its occurrence frequency ranges from 0 % to 80 %. The Atlantic influence is quite propitious to the species, whereas the Mediterranean climate is not. The supramediterranean series of Quercus pubescens is not convenient for the species. The presence of Ixodes ricinus was ascertained at numerous sites in forests belonging to the Atlantic series of Quercus pedunculata as well as in the artificial pine forest of Pinus maritimus. Dermacentor reticulatus is the other tick species the most frequently encountered in the same forests as Ixodes ricinus in the study area.