Lyme disease epidemiology and surveillance
Updated 14 April 2022
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Background
Lyme disease is the most common vector-borne human infection in England and Wales. As elsewhere in northern Europe, the spirochaetes (Borrelia burgdorferi) are transmitted by the hard bodied tick, Ixodes ricinus, commonly known as deer or sheep ticks.
Habitats suitable for acquiring infection occur in temperate regions of the northern hemisphere, usually in forested woodland or heathland areas which support the life-cycles of ticks and the small mammals and birds that can be reservoir hosts for B. burgdorferi.
Several pathogenic genospecies of B. burgdorferi have been identified in Europe and there is evidence for some variation in the types of clinical presentation caused by these different genospecies.
Surveillance
Lyme disease is monitored in England and Wales through routine surveillance. The UK Health Security Agency (UKHSA) Rare and Imported Pathogens Laboratory (RIPL) provides Lyme disease laboratory testing services for England and Wales and data are published in the quarterly Health Protection Reports. Acute Lyme disease data by local authority in England is available on UKHSA’s Fingertips platform.
Cases of Lyme disease are not statutorily notifiable by medical practitioners in England, Wales and Northern Ireland. However, since October 2010 under the Health Protection (Notification) Regulations 2010, every microbiology laboratory (including those in the private sector) in England is required to notify all laboratory diagnoses of Lyme disease to UKHSA.
A Lyme disease enhanced surveillance scheme ran between 1997 and 2003 in England to improve reporting and to collect additional clinical and epidemiological information on cases. The data collected helped to enhance knowledge of Lyme disease at that time.
Annual totals and rates
The data reported refer to laboratory-confirmed cases of Lyme disease in England and Wales, but do not include cases diagnosed and treated on the basis of clinical features such as erythema migrans (the early rash of Lyme disease) , as per NICE guidelines without laboratory confirmation or cases diagnosed at local NHS or private laboratories but not sent to RIPL for confirmation.
It has been estimated that, in addition to the laboratory-confirmed cases, there are also between 1,000 and 2,000 additional cases of Lyme disease each year in England and Wales that are not laboratory-confirmed.
Laboratory-confirmed cases of Lyme disease in England and Wales have risen steadily since reporting began in 1986 although yearly fluctuations have been observed. Mean annual incidence rates for laboratory-confirmed cases have risen from 0.38 per 100,000 population for the period 1997 to 2000, to a peak of 2.77 cases per 100,000 population in 2018.
Since 2018, there has been a slight decrease in annual rates but impacts of the coronavirus (COVID-19) pandemic on both human behaviour, diagnostics, and health-seeking behaviour, are unclear.
The overall rise in the total laboratory confirmed cases may be due to a combination of increased awareness of the disease among the public and healthcare professionals, improved surveillance and access to diagnostic testing, increased potential for encounters with ticks due to changes in wildlife populations and human behaviour, changes in the distribution of ticks and possible extensions of tick activity periods.
Laboratory reports of Lyme disease in England and Wales: annual totals and rates, 2013 to 2021
| Years | Total laboratory confirmed cases | Mean annual rate per 100,000 population |
|---|---|---|
| 2013 | 936 | 1.64 |
| 2014 | 856 | 1.49 |
| 2015 | 1,060 | 1.83 |
| 2016 | 1,134 | 1.94 |
| 2017 | 1,584 | 2.70 |
| 2018 | 1,636 | 2.77 |
| 2019 | 1,639 | 2.76 |
| 2020 | 1,262 | 2.11 |
| 2021* | 1,156 | 1.94** |
*Provisional data. **Rates for 2021 have been calculated using the Office for National Statistics’ (ONS) 2020 mid-year population estimates as a proxy as figures for 2021 were not available at the time of publication.
Demographics and seasonality
Based on laboratory-confirmed Lyme disease, cases occur in people of all ages and both sexes are equally susceptible. Peaks in cases are seen in those aged between 45 and 64 years, followed by those aged from 25 to 44 years.
Lyme disease is more commonly diagnosed during the summer season, coinciding with tick activity and higher levels of outdoor human activity that may result in tick exposure, but cases are reported throughout the year.
Most of these cases probably acquired infection in late spring and early summer, allowing for the time period between being bitten, developing symptoms, and developing levels of antibodies high enough to give positive results on laboratory tests.
This is also consistent with the peak tick feeding period of late spring and early summer.