Lyme borreliosis and other tick-borne diseases. Guidelines from the French Scientific Societies (I): prevention, epidemiology, diagnosis.

Lyme borreliosis is transmitted en France by the tick Ixodes ricinus, endemic in metropolitan France. In the absence of vaccine licensed for use in humans, primary prevention mostly relies on mechanical protection (clothes covering most parts of the body) that may be completed by chemical protection (repulsives). Secondary prevention relies on early detection of ticks after exposure, and mechanical extraction. There is currently no situation in France when prophylactic antibiotics would be recommended. The incidence of Lyme borreliosis in France, estimated through a network of general practitioners (réseau Sentinelles), and nationwide coding system for hospital stays, has not significantly changed between 2009 and 2017, with a mean incidence estimated at 53 cases/100,000 inhabitants/year, leading to 1.3 hospital admission/100,000 inhabitants/year. Other tick-borne diseases are much more seldom in France: tick-borne encephalitis (around 20 cases/year), spotted-fever rickettsiosis (primarily mediterranean spotted fever, around 10 cases/year), tularemia (50-100 cases/year, of which 20% are transmitted by ticks), human granulocytic anaplasmosis (<10 cases/year), and babesiosis (<5 cases/year). The main circumstances of diagnosis for Lyme borreliosis are cutaneous manifestations (primarily erythema migrans, much more rarely borrelial lymphocytoma and atrophic chronic acrodermatitis), neurological (<15% of cases, mostly meningoradiculitis and cranial nerve palsy, especially facial nerve) and rheumatologic (mostly knee monoarthritis, with recurrences). Cardiac and ophtalmologic manifestations are very rarely encountered.