Lyme disease, also known as Lyme borreliosis, is a bacterial infection that occurs in Europe, including the UK, North America and in temperate areas of Asia.
Lyme disease is transmitted to humans by infected ticks, mainly the sheep/deer tick. Not every tick carries the infection.
- Infection is transmitted during blood feeding on humans. Once a tick attaches to skin it remains feeding for several days.
- Lyme bacteria are present in the tick gut and it takes time for them to become infective to humans and be transmitted during feeding.
Infection is unlikely to be transmitted if ticks are removed within the first 24 hours of becoming attached to skin.
The first sign of infection is often a rash at the attachment site that appears after 3 – 30 days. The rash is red and gradually expands outwards over days. It is not usually itchy or painful. Other symptoms may include fever, headache, chills, fatigue, joint pains, muscle ache and swollen glands. The rash gradually gets better over weeks.
A red, itchy rash that appears and gets better in the first 2 days after tick attachment is usually due to a local reaction to the tick itself and is not a sign of Lyme infection.
If the infection is not treated, within a few days to weeks the infection may spread to other areas of the body and could affect the heart, nervous system and joints.
Lyme disease can be treated with antibiotics.
The risk of Lyme disease is greatest for travellers to North America, Europe and temperate regions of Asia, who are involved in outdoor activities in wooded/grassy areas and moorland, such as camping, walking, hiking. Ticks can also be found in urban parks and gardens
There is no vaccine available against Lyme disease.
The main preventive measure against Lyme disease is to avoid being bitten by ticks, and to remove ticks as soon as possible (within the first day) after attachment, to reduce the risk of transmission of Lyme disease.
For information on avoiding tick bites in the UK see NHS Inform Avoiding bugs and germs outdoors