What is Lyme disease?

Lyme disease, also known as Lyme borreliosis, is an infectious disease caused by the bacterium Borrelia burgdorferi. The disease is classified by the World Health Organisation as an infectious or parasitic disease. B burgdorferi belongs to the bacterial genus ‘Borrelia’. These in turn are members of a larger family of bacteria called Spirochaetes. [1]

How does Lyme disease infection occur?

In nearly all recorded cases it is transmitted to humans by the bite of a tick infected with these bacteria. [1] In a population of ticks, only some will carry the infection. LDA has raised concern and highlighted the need for further research in this area, to resolve ongoing uncertainty concerning the possibility of alternative means of transmission such as congenital or via sexual contact.

What is Borreliosis?

The disease resulting from infection with Borrelia burgdorferi is referred to as Lyme disease or Lyme borreliosis. There are many species of Borrelia bacteria worldwide, not all of them cause disease. Four species known to cause disease are present in UK ticks. They are B burgdorferi (sensu stricto), Borrelia afzelii,  Borrelia garinii and Borrelia miyamotoi.[2] The first three are very closely related and all cause a broadly similar disease process; B miyamotoi is more closely related to the relapsing fever group of Borrelia. An infection caused by Borrelia bacteria can be termed a ‘Borreliosis.’

How does Lyme disease start?

A clinical case of Lyme disease occurs when a person is infected by a tick bite. Symptoms appear on average 14 days after the tick bite. However the incubation period may last between two days and 3 1/2 months.[3] The bacteria can enter a phase in which they do not cause symptoms but are still present. They may still have the potential to cause active disease at a later stage.[4]

Is Lyme disease a new illness?

Studies of the DNA taken from ticks in the Natural History Museum show Borrelia bacteria were in the UK in Victorian times. However, although known in mainland Europe for more than a century, the first recorded case of an erythema migrans in the UK was in 1977 and the number of Lyme disease cases has been rising since then.[5]


What are the symptoms of Lyme disease?

Lyme disease can affect any part of the body and cause many different symptoms. The commonest symptoms relate to the person feeling unwell, having flu-like symptoms, extreme tiredness, muscle pain, muscle weakness, joint pain, upset digestive system, headache, disturbances of the central nervous system and a poor sleep pattern. In some cases an expanding ‘bull’s eye’ rash appears on the skin. However, a rash in any form is not a universal symptom. If the rash does occur, it is termed erythema migrans or EM rash. It may manifest in a chronic form and be known as erythema chronicum migrans or ECM rash. The list of symptoms known to be associated with Lyme disease is long and diverse. The symptom pattern varies from person to person.[1]

What are the commonest symptoms at onset?

Early symptoms can include feeling unwell or ‘flu-like’, EM rash, headache, stiff neck, muscle pain, tender glands and sensitivity to temperature, sound and light levels.[1]

Does Lyme disease affect mental functioning?

Like some other diseases caused by spirochaetes, there is a possibility that the infection can cross into the central nervous system. If the infection proceeds along this course then symptoms that affect mental function may occur.[2]


What is the treatment for Lyme disease?

Treatment is with antibiotics and is most effective if started as early as possible in the disease. Those treated promptly usually make a complete recovery. There is growing scientific and anecdotal evidence that suggests re-treatment, longer courses of antibiotics and possibly combinations of antibiotics may be necessary in some cases. [6,7] Treatment is aimed at reduction and elimination of the bacteria. If there is delay before treatment begins, there may be less chance of a full recovery. The outlook varies from person to person. Whilst it is extremely unusual for the illness to be fatal, symptoms can range from mild to very severe. It is not in a patient’s best interests for the disease to remain untreated.

Will my doctor treat me for Lyme disease?

If you have this diagnosis your doctor should treat you. However, many doctors are not familiar with treating Lyme disease patients.  Always try to keep your GP involved and informed. See the page Resources/For patients for information to give to your doctor. A worsening of symptoms called a Jarisch-Herxheimer reaction may complicate the start of treatment. This does not occur in every case but if it does further medical advice should be sought. Lyme disease is an infectious disease and the primary aim of treatment is eliminating the infection with the help of antibiotics. Other medicines may also have a place in treatment. Response to treatment varies from patient to patient.


Is there a test for Lyme disease?

There are several laboratory tests that aim to detect this infection, however, none of them can be guaranteed to rule out Lyme disease. If positive they can be used to support the diagnosis.

How do I know if I’ve got Lyme disease?

Lyme disease is not an easy diagnosis to make. This is especially so if the patient has no rash and does not recall a tick bite. If a patient remembers a tick bite and then becomes unwell, Lyme disease is a possibility. Negative test results do not necessarily exclude a diagnosis of Lyme disease and the diagnosis may sometimes be made on clinical grounds alone. See our Self Help page.

Lyme in the UK

What is the incidence of Lyme disease in the UK?

The number of cases confirmed by laboratory testing in the UK has risen from 346 in 2003 to about 1700 in 2017. Public Health England (PHE) acknowledges that confirmed cases do not necessarily reflect all the cases of the disease. PHE official estimates suggest there could be up to 3,000 new cases occurring in the UK every year. The true number of cases is not known, and is probably much higher. Since full recovery may not take place in many cases, the total number of people affected is accumulating.

Who gets Lyme disease and why?

In the United Kingdom, Lyme disease is known to be carried mainly by small mammals, such as mice and voles, and birds, though larger mammals can also carry it. Ticks feeding on these animals pick up the Lyme disease bacteria and pass them on to the next animal they feed on. The principal tick that attaches to humans is the sheep tick, Ixodes ricinus but the hedgehog tick I hexagonus and the fox or English dog tick I canisuga can sometimes attach too. Ticks can also feed on deer, cattle and sheep, which appear to kill off the bacteria in the tick (9).  The sheep tick prefers to live in long grass, woods and moorland, although it does not occur exclusively in these habitats. The other two species of tick live mainly in the homes of their hosts (hedgehogs, foxes and badgers) but can be found wherever these animals travel. People who live or work in the parts of the country where the ticks are prevalent are likely to be at greater risk, as are those in urban areas with overgrown gardens or with extensive parks. However, cases of the disease are widespread and it is possible that the full picture of tick distribution is not yet fully understood. Anyone can get Lyme disease if a tick that is carrying the infection has bitten them.

Do other diseases accompany Lyme disease?

Several other infections can sometimes be found in tick saliva. These can also be transmitted as the tick feeds and may complicate the symptoms and outlook.

Can Lyme disease be prevented?

There are many measures you can take to protect yourself from contracting this infection.[8] There is however, no vaccine available at present. Prevention relies on people being aware of the risk that ticks present and using sensible measures to avoid being bitten. These measures include wearing suitable clothing and checking the skin for ticks. It is also essential to know how to remove a tick properly if it is still present and to go promptly for medical advice if you notice any symptoms.


  1. Stanek G, Wormser GP, Gray J, Strle F. Lyme borreliosis. Lancet. 2011 Sep 6;6736(11):1–13.
  2. Williams F, Ginsberg L, Brenner R, Cohen A. An exotic cause for confusion in the garden. Pract Neurol. 2008 Aug;8(4):256–9.
  3. Logar M, Ruzić-Sabljić E, Maraspin V, Lotric-Furlan S, Cimperman J, Jurca T, et al. Comparison of erythema migrans caused by Borrelia afzelii and Borrelia garinii. Infection. 2004 Feb;32(1):15–9
  4. Matera G, Labate A, Quirino A, Lamberti AG, Borzì G, Barreca GS, et al. Chronic neuroborreliosis by B garinii: an unusual case presenting with epilepsy and multifocal brain MRI lesions. New Microbiol. 2014;37:393–7.
  5. Obasi O. Erythema chronicum migrans. Br J Dermatol. 1977;97:459.
  6. Dillon R, O’Connell S, Wright S. Lyme disease in the U.K.: clinical and laboratory features and response to treatment. Clin Med. 2010 Oct;10(5):454–7.
  7. Feng J, Auwaerter PG, Zhang Y. Drug Combinations against Borrelia burgdorferi Persisters In Vitro : Eradication Achieved by Using Daptomycin , Cefoperazone and Doxycycline. PLoS One. 2015;1–15.
  8. Goodyer LI, Croft AM, Frances SP, Hill N, Moore SJ, Onyango SP, et al. Expert review of the evidence base for arthropod bite avoidance. J Travel Med. 2010;17(3):182–92.
  9. Richter D, Matuschka F-R. Elimination of lyme disease spirochetes from ticks feeding on domestic ruminants. Appl Environ Microbiol. 2010 Nov;76(22):7650–2