International travel and health

Lyme Borreliosis (Lyme disease)


The spirochaete Borrelia burgdorferi, of which there are several different serotypes.


Infection occurs through the bite of infected ticks, both adults and nymphs, of the genus Ixodes. Most human infections result from bites by nymphs. Many species of mammals can be infected, and deer act as an important reservoir.

Nature of the disease

The disease usually has its onset in summer. Early skin lesions have an expanding ring form, often with a central clear zone. Fever, chills, myalgia and headache are common. Meningeal involvement may follow. Central nervous system and other complications may occur weeks or months after the onset of illness. Arthritis may develop up to 2 years after onset.

Geographical distribution

There are foci of Lyme borreliosis in forested areas of Asia, north-western, central and eastern Europe, and the USA.

Risk for travellers

Generally low except for visitors to rural areas, particularly campers and hikers, in countries or areas at risk.




Avoid tick-infested areas and exposure to ticks (Chapter 3). If a bite occurs, remove the tick as soon as possible.