Lyme Disease is caused by bacteria belonging to the genus Borrelia transmitted through the bite of infected ticks belonging to the Ixodes genus. Borrelia burgdorferi is the predominant cause of the illness in North America, and Borrelia afzelii and Borrelia garinii in Europe and Asia. Ticks get infected when they feed on deer, birds, and rodents who are reservoirs for the bacteria and spread it to humans typically by nymphs (immature ticks).
Lyme Disease is present in North America, Europe, and Asia. Travellers involved in outdoor activities in forested areas are at risk, including campers, hikers, and hunters. Brushing against vegetation or walking in city parks known to have infected ticks can also put a person at risk.
Lyme Disease usually progresses in three stages. One of the first symptoms (for approximately 70% to 80% of persons) is a small bump and skin rash at the site of the bite which usually goes away after 1 or 2 days. Anywhere from 3 to 30 days, the rash expands to an encircled red patch (known as Erythema migrans or Bull's Eye rash) which is warm to the touch but not painful or itchy. The rash may produce lesions. Other symptoms include fever, headache, muscle and joint pain, chills, fatigue, and swollen lymph nodes. Contact your healthcare practitioner immediately if you develop symptoms.
If untreated, the illness progresses to the second stage within days or weeks of getting infected. Symptoms include severe headaches, meningitis, swollen joints, skin lesions, heart palpitations, dizziness, persistent fatigue, sleep disturbance, as well as loss of muscle tone in the face (Bell's palsy). Some of these symptoms usually disappear within weeks or months. However, if untreated, the illness will progress to a third stage which includes arthritis and chronic pain, numbness, tingling of hands and feet, and short-term memory loss.
If treated promptly, Lyme Disease usually takes 2 to 4 weeks to cure and includes antibiotics such as doxycycline, amocicillin, or ceftriaxone.
Travellers who engage in hiking, camping, or similar outdoor activities in wooded regions of endemic areas should take measures to prevent tick bites, including applying a DEET-containing repellent to exposed skin and permethrin spray (or solution) to clothing and gear. When hiking in wooded areas, stay in the middle of the trail and avoid tall grasses and shrubs. Wear light coloured clothing, and long shirts and pants tucked into socks. Carefully examine your clothing, gear, and pets for ticks before entering a dwelling.
Regularly check your body for ticks and promptly remove using tweezers by grasping the tick's head and mouth parts as much as possible and by pulling perpendicular from the skin. Thoroughly disinfect the bite site with soap and water or alcohol. If travelling in an endemic area, you may want to save the tick in a zip-lock bag or empty container to have it analyzed through your healthcare practitioner. There is no preventive vaccine or medication against Lyme Disease.
>> For Lyme Disease images, life cycle, and distribution maps, see Infection Landscapes.