Lyme disease is a complex illness and there is conflicting information reported in the media. This page pulls together the key facts from reliable sources.
Hyperlinks to the original sources are provided throughout this page. Sources include:
- NICE (The National Institute for Health and Care Excellence)
- Public Health England
- NHS Choices
- The World Health Organisation
- The European Centre for Disease Control
Ten quick facts
1) Lyme disease is caused by a corkscrew-shaped bacteria called Borrelia. There are different strains of the bacteria, including Borrelia burgdorferi, Borrelia afzelii and – believed to be the commonest one in Britain – Borrelia garinii.
2) Borrelia is known to be transmitted through the bite of an infected tick. It may also be spread congenitally from infected mother to baby, but it is not known how high the risk is. It is not known whether it can be spread through blood transfusions, so more research is needed to clarify the likelihood of this risk. You cannot catch Lyme disease through normal social contact with infected people. (Source: NICE guideline for Lyme disease)
MORE INFORMATION: Lyme disease in pregnancy
3) Ticks are found in city parks and urban gardens as well as open countryside. They climb up plants, and brush onto skin or clothing as you pass. They are found in every part of the UK. You will not feel a tick biting you, so you have to do a visual check. They can crawl up inside clothing and even get into underwear without you feeling them. (Source: NICE guideline for Lyme disease)
MORE INFORMATION: How to protect your family and pets
4) Dog and cat owners who stay alert often find ticks on their pets, and they can easily be brought into the house. Nymph ticks can be as small as a poppy seed and are very hard to spot. A proper tick remover used according to the instructions is the best way to remove a tick.
5) Beware of INCORRECT and potentially dangerous instructions on tick removal. This video demonstrates safe tick removal:
6) Lyme disease attachs the nerves and brain, joints, heart, eyes and can often cause a distinctive skin rash. Early symptoms are often similar to flu, namely fevers, night sweats, swollen glands, muscle and joint pain, nausea, a stiff neck and headaches and very severe fatigue. The disease also attacks the nervous system and brain, causing pain, paralysis, tingling or pins and needles, or numbness. In the brain it can cause psychosis/mental illness. It can attack the eyes and cause soreness or blindness. Lyme can cause arthritis in one or more joints. (Source: NICE guideline for Lyme disease.)
MORE INFORMATION: Lyme disease symptoms
7) A reddish rash, which spreads out and may form rings, is unique to Lyme disease. It is estimated that a third of Lyme disease patients never have the rash (Source: Public Health England) however other sources estimate significantly different percentages. Lyme disease often has no visible symptoms.
8) Lyme disease symptoms take up to 3 months to develop. This means a tick bite at the end of summer could give you symptoms at Christmas – just in time to mistake the illness for flu. (Source: NICE guideline for Lyme disease.)
9) Blood tests for Lyme disease are not highly reliable. It is recommended that the doctor repeats the test if Lyme disease symptoms persist, and even diagnoses Lyme disease with a negative test result if symptoms present a clear picture of lyme disease. (Source: NICE guideline for Lyme disease.)
10) Lyme disease should be treated with antibiotics, ideally within six weeks of being infected. Initial treatment usually lasts 3 or in some cases 4 weeks, and a second course of antibiotics may be needed for some people. Patients diagnosed later than six weeks after being infected are given the same treatment. Some patients still have symptoms after this treatment, and there is currently no test to tell whether they still have the bacterial infection, or if they instead have tissue damage resulting from the illness. Research is needed to answer this question. (Source: NICE Guideline for Lyme disease)
Lyme disease cases in the UK
In the UK, PHE estimates around 3,000 people are diagnosed with Lyme disease each year. In other words, 8 people are infected every day. (Source: Public Health England).
However, actual statistics are not recorded and this may be an underestimate. A study from 2019 found that cases of Lyme recorded by GPs suggest there may be around 9,000 cases a year. It also found cases increased ten-fold between 2001 and 2012.
Rapidly increasing across Europe
Lyme disease is the fastest spreading, and the most common, vector borne disease in Europe, according to the World Health Organisation. (“Vector borne” means that it is spread from human to human by a biting animal).
Lyme disease has been increasing in Europe at 14% a year for the last 20 years, faster than AIDS, Malaria and Measles (SOURCE: World Health Organisation)
In Europe, aggregated national figures for the whole region are published by the World Health Organisation and the European Centre for Disease Control. Published on the CISID website, they record that newly diagnosed cases of Lyme disease were around 2,400 in 1990 and had risen to 35,000 by 2010.
Download: WHO / ECDC Information sheet on Lyme disease
Link: WHO/ECDC/CISID website
Over this 20-year time period, new cases of Lyme disease in Europe increased by about 1,300%, which equates to an annual average growth of 65% each year relative to the number of patients in 1990. In reality, as the graph shows, the increase was more than this in some years and less in others.
The compound annual growth rate over this time period, showing the year-on-year growth, was 14%. This figure is the median year-on-year increase over the two decade time period, but in reality growth accelerated at a higher rate than this between 1997 and 2006, and then levelled off between 2006 and 2010. Frustratingly, the WHO/ECDC has not published more recent aggregated figures.
We do know, however, that reporting standards and methods of gathering data vary from each European country to the next, and also over time. In the UK, for example, official figures only report on the minority of patients diagnosed by blood test, whilst the majority, who are diagnosed by EM rash, are excluded from the reported data. Similar anomalies exist across the continent and result in significant under-reporting.
A research paper aiming to adjust the figures and arrive at a more representative estimate was published by The Journal of Public Health in 2016, and concluded:
“LB (Lyme Borreliosis) is a continually emerging disease and the most common zoonotic infection in Western Europe approaching endemic proportions in many European countries.”
Download: An estimate of Lyme borreliosis incidence in Western Europe, Robert A Sykes
Link to Source: Journal of Public Health
How does this compare with other diseases?
Lyme disease is the most common of the vector-borne diseases in Europe. Vector-borne disease are infections spread by biting insects, arachnids and other parasitic animals.
Lyme disease is the fastest spreading vector-borne disease in Europe. (Source: World Health Organisation)
Zsuzsanna Jakab, WHO Regional Director for Europe said at a WHO conference in 2014:
“There is a clear warning signal to the European Region that diseases carried by vectors may spread and intensify in the years ahead. This is not the time to lower our guard.”
Whilst the incidence of Malaria is now falling sharply in Europe, Lyme disease is persistently increasing. As this graph produced by the WHO shows, Lyme disease is spreading far faster than other vector-borne illnesses in Europe:
Key: Vector-borne diseases in this graph are Lyme disease (ticks), Malaria (mosquitoes), West Nile Fever (WNF) (mosquitoes), Tick-Borne Encephalitis (TBE) (ticks), Crimean-Congo Haemorrhagic Fever (ticks) and Leishmaniasis (sandflies).
Source: Download PDF presentation World Health Day 2014 VECTOR BORNE DISEASES (EUROPE)
Lyme disease is also spreading faster than some other worrying diseases in Europe. This graph shows the increase in new cases of HIV-AIDS, Measles and Lyme disease throughout Europe from 1991 to 2010 (Source: CISID – World Health Organisation)
Why is Lyme disease spreading so fast?
One of the contributing factors to increases in Lyme disease incidence would be changes in the weather, and thus in the tick population, and in the numbers of people spending time outside, and in how much clothing they were wearing to protect their skin.
The sheep tick (Ixodes Ricinus) is the most common tick in the UK. One theory is that, due to climate change and warmer weather, tick reproductive activity appears to be increasing, and in particular benefitting from earlier, warmer springtime weather. Ticks climb up long grass and other plants and attach to passing mammals; clearly humans with bare legs are more vulnerable than those in long trousers.
Another theory is that humans are simply building on more and more greenfield sites, which have traditionally been tick habitats, and are therefore coming into more frequent contact with the arachnids.
Another driving factor could be the presence of pets. The University of Bristol, UK, has an ongoing research project called the Big Tick Project which asked veterinarians across the UK to conduct spot check on dogs and cats brought into their consulting rooms and report the numbers of ticks they find. They found that 1 out of 3 dogs in the UK has a tick feeding from it in spot checks. (Source: The Big Tick Project)
It is easy to see how ticks which attach unnoticed to dogs walking in the countryside may then detach when the same dogs are taken to an urban park, or even in their owner’s garden, and thus a tick population may begin to establish itself in a new spot. A recent research project found ticks carrying Lyme disease in Richmond Park and Bushy Park in London. (Source: Medical and Veterinary Entomology)
The de facto hosts of ticks are small, ground-dwelling mammals including mice, squirrels and also some birds. These animals spread widely and also come into close proximity with human dwellings and recreation areas.
So far, no systematic research has been done to establish facts. One research paper, reported finding that 6% of ticks in a region of the UK it researched were carrying Borrelia Burgdorferi. Another paper, in another region, found 25%. These are really nothing more than “spot checks” but we do know that levels vary greatly by region and, indeed, from one year to another.
DISCLAIMER: Caudwell LymeCo charity shares public domain information, which it believes to be reliable, in good faith. It should never replace the advice of a qualified physician with a license to practise medicine. If you believe any information on this website to be incorrect, you are invited to contact the charity using the Contact page.