Lyme disease

Lyme disease, also known as Lyme borreliosis, is a vector-borne disease caused by Borrelia bacteria, which are spread by ticks in the genus Ixodes. The most common sign of infection is an expanding red rash, known as erythema migrans (EM), which appears at the site of the tick bite about a week afterwards. The rash is typically neither itchy nor painful. Approximately 70–80% of infected people develop a rash. Early diagnosis can be difficult. Other early symptoms may include fever, headaches and tiredness. If untreated, symptoms may include loss of the ability to move one or both sides of the face, joint pains, severe headaches with neck stiffness or heart palpitations. Months to years later, repeated episodes of joint pain and swelling may occur. Occasionally, shooting pains or tingling in the arms and legs may develop. Despite appropriate treatment, about 10 to 20% of those affected develop joint pains, memory problems, and tiredness for at least six months. Lyme disease is transmitted to humans by the bites of infected ticks of the genus Ixodes. In the United States, ticks of concern are usually of the Ixodes scapularis type. "In most cases, a tick must be attached for 36 to 48 hours or more before the Lyme disease bacterium can be transmitted. If you remove a tick quickly (within 24 hours), you can greatly reduce your chances of getting Lyme disease." In Europe, Ixodes ricinus ticks may spread the bacteria more quickly. In North America, the bacterial species Borrelia burgdorferi and B. mayonii cause Lyme disease. In Europe and Asia, Borrelia afzelii, Borrelia garinii, B. spielmanii and four other species also cause the disease. The disease does not appear to be transmissible between people, by other animals nor through food. Diagnosis is based on a combination of symptoms, history of tick exposure and possibly testing for specific antibodies in the blood. Blood tests are often falsely negative in the early stages of the disease. Testing of individual ticks is not typically useful.