Definition Lyme disease is a spirochete (a germ similar to a bacterium) infection that is passed to humans through tick bites.
What is going on in the body? After a bite from an infected tick, it usually takes a week for the first symptoms of Lyme disease to appear. However, it can take as little as 3 days or as long as 31 days. The hallmark of Lyme disease is the so-called bulls-eye rash, a red, circular rash that is clear in the centre. It appears at the site of the tick bite in most infected individuals, usually in the armpit or on the trunk, thigh, or buttock. Lyme disease has been reported in 48 states of the US and in Europe. It occurs most often in the summer. Two kinds of ticks are known to pass the bacteria to humans. The existence of the disease in Australia remains controversial and unproven.
What are the signs and symptoms of the disease? The most obvious sign of Lyme disease is the bulls-eye rash. It starts as a red, circular lesion. As it gets bigger, the centre often clears so that the skin looks normal in the middle. Other symptoms may accompany the rash, especially if the disease is untreated. These symptoms include:
When a person is not treated, symptoms tend to come and go over a number of weeks.
What are the causes and risks of the disease? Lyme disease is caused by the spirochete Borrelia Burgdorferi. Living in an area where the ticks that carry Lyme disease are found increases the risk of getting the disease.
What can be done to prevent the disease? People can prevent Lyme disease by avoiding tick bites. There are several tips to help prevent lyme disease.
Individuals should wear protective light-coloured clothing such as high boots and pants when walking in areas with woods or tall grasses that might have ticks.
People should use a tick repellent containing DEET.
Individuals need to check carefully every day to be sure there are no ticks on the body. It takes 24 hours for a tick attached to the body to pass the spirochete on. Removing a tick before that can prevent the disease.
A vaccine to prevent the disease is available in the USA.
How is the disease diagnosed? Early Lyme disease is usually diagnosed by the presence of the bulls-eye rash. A blood test for antibodies (chemicals the body makes against the spirochete) is often done to confirm the diagnosis. The spirochetes that cause Lyme disease can be cultured (grown in the lab) from blood or a biopsy of the rash, too. However, this is rarely done.
What are the long-term effects of the disease? When the disease is untreated for months, people may develop:
nervous system complications, including facial palsies (paralysed muscles in the face)
What are the risks to others? People with untreated Lyme disease can pass it on by donating blood.
What are the treatments for the disease? Antibiotics are given to treat Lyme disease: doxycycline is usually used for adults, amoxicillin or penicillin is usually used for children younger than 9 years old, ceftriaxone is used for certain forms of late Lyme disease
What are the side effects of the treatments? Side effects vary with the medication used. Some of the more common side effects of these medications are:
photosensitivity, or abnormal sensitivity to light
Author: Danielle Zerr, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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