USING A VEGETAL INDICATOR TO CARTOGRAPHY THE POPULATIONS OF AN EXOPHILE TICK ON THE SCALE OF A COUNTRY - THE EXAMPLE OF IXODES-RICINUS, A VECTOR OF LYME-BORRELIOSE IN FRANCE
B. Doche et al., USING A VEGETAL INDICATOR TO CARTOGRAPHY THE POPULATIONS OF AN EXOPHILE TICK ON THE SCALE OF A COUNTRY - THE EXAMPLE OF IXODES-RICINUS, A VECTOR OF LYME-BORRELIOSE IN FRANCE, Annales de Parasitologie humaine et comparee, 68(4), 1993, pp. 188-195
In Western Europe, Ixodes ricinus has been recognized as the vector of
several animal and human diseases. The last discovered nosological en
tity linked with that species is Lyme Borreliosis, whose repartition i
s to date badly known. It then becomes important to have a comprehensi
ve view of the vector distribution in order to know what areas are pro
pitious to the disease. The tick is an exophile species and lives more
particularly in wooded areas. For mapping the species in France, we h
ave conceived a method L using the different vegetation types as ecolo
gical indicators, each << series >> having homogeneous environmental c
onditions. The successive steps in the accomplishment of the study (fr
om the zoning of the territory to the tick sampling) are presented her
e (Use of small and medium scale vegetation maps, fixing the forest st
ations to be prospected, standardization of the flagging technique). S
ome results are analysed here in order to give an idea and the limits
of the method. In this purpose, the authors point out the results obta
ined in two different areas. In South-Western France, the vegetation s
eries can be easily distinguished and are largely variable from one ar
ea to another. In the present study, the tick frequencies are also pro
ved to be varying from one << series >> to an other. In this case, the
vegetation can be considered as an efficient indicator. The acarologi
cal data are obviously in connection with the ecological variability o
f the territory. As regard of Brittany (North-Western, France) because
the homogeneity and uniformity of the area, the vegetation series can
not be distinguished continuously. So the use of the vegetal indicator
from the reason that has been exposed, can be thought of little inter
est.