Bio-écologie et rôle pathogène des tiques de France métropolitaine

Abstract

All stages of ticks are hematophagous parasites and they live mostly independent of their hosts. These large size mites have a hypostome for attachment to host skin and blood feeding ticks are of considerable importance in humans and veterinary diseases. Indeed, their salivary secretions have neurotropic or even paralyzing properties.Moreover they can be reservoir host and have vector competences in many diseases: viral (arboviroses), bacterial (borreliosis, rickettsialisis disease, ehrlichiosis or anaplasmosis) and parasitic diseases (babesiosis, filariosis).For most pathogens transmission is horizontal (transstadial) and transovarial for maintaining in a tick population it explains the sometimes focal nature of transmitted diseases.Thy are two main families: Ixodidae or hard ticks (700 species) and Argasidae or soft ticks (200 species). Ticks have worldwide distribution both hot and cold areas. They are temporary parasitic arthropods, strictly hematophagous with three stages after eggs: larvae, nymphs and male or female adults. Larvae are hexapods whereas nymphs and adults are octopods. Human is an accidental host. In France, the main species involved in human pathologies are Ixodes ricinus (Lyme borreliosis, tick-borne encephalitis. anaplasmosis), Rhipicephalus sanguineus (Mediteranean spotted fever), Dermacentor marginatus and D. reticulatus (Tibola, Tick-borne lymphadenopathy) and Argas reflexus (inflammatory lesions).