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Vector-borne diseases

Lyme disease

Lyme disease (Lyme Borreliosis) is caused by Borrelia bacteria and is transmitted through the bite of infected deer ticks (of the Ixodes species). Many species of mammals can be infected and rodents and deer act as important reservoirs.

The first recognized outbreak of this disease occurred in Connecticut, United States, in 1975. The current burden is estimated at 7.9 cases per 100 000 people in the United States, according to the US Centers for Disease Control and Prevention.

Since the mid-1980s, the disease began to be reported in several European countries. Lyme disease occurs in rural areas of Asia, north-western, central and eastern Europe, and the United States of America. It is now the most common tick-borne disease in the Northern Hemisphere.

People living in or visiting rural areas, particularly campers and hikers, are most at risk. If bitten, the tick should be removed as soon as possible

Lyme disease symptoms include fever, chills, headache, fatigue, muscle and joint pain. A rash often appears at the site of the tick bite and gradually expands to a ring with a central clear zone, before spreading to other parts of the body. If left untreated, infection can spread to joints, the heart and central nervous system. Arthritis may develop up to 2 years after onset.

Most cases of Lyme disease can be treated successfully with a course of antibiotics.