B. Gilot et al., ACAROLOGICAL DATA FOR THE ECO-EPIDEMIOLOG IC STUDY OF LYME-BORRELIOSIS - IXODES-RICINUS LINNE, 1758 - POPULATIONS IN SOUTH WESTERN FRANCE, Acarologia, 36(2), 1995, pp. 117-132
In Order to understand how Lyme Borreliosis foci are generated on the
French territory, a complete picture of the true distribution of the t
ick vector Ixodes ricinus is required. A set of fundamental data was a
cquired through a method using plant communities as indicators. The re
sults presented in this article are related to the South-Western quadr
ant 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-ecolo
gical and geographical units. Seventeen units were delineated. In a ra
nge 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 p
eriod 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 t
he Mediterranean climate is not. The supramediterranean series of Quer
cus pubescens is not convenient for the species. The presence of Ixode
s ricinus was ascertained at numerous sites in forests belonging to th
e Atlantic series of Quercus pedunculata as well as in the artificial
pine forest of Pinus maritimus. Dermacentor reticulatus is the other t
ick species the most frequently encountered in the same forests as Ixo
des ricinus in the study area.