The aim of the study was to precise the geographical repartition of
Lyme borreliosis in the Rhône-Alpes district, to describe the ecological characteristics of the areas propitious to the
disease, and to verify the vectorial competence of I. ricinus. The cases of
Lyme disease were located by means of a questionnaire sent to 1156 physicians. The vector role of I. ricinus was studied by two ways: firstly by searching a correlation between the geographical repartition of the tick and that of cases, secondly by proving the Borrelia infection of the tick.
Lyme disease is widely spread in the study area, mainly at the foothill level, its repartition is largely coinciding with that of I. ricinus which was found infected by B. burgdorferi (s.l.). However a few cases, located near the Mediterranean area, set an unanswered problem.