Diseases carried by UK ticks

Several infections are carried by UK ticks (1-3) but distribution and rate of infection is not fully documented. In studies of UK ticks, Lyme disease is by far the most common infection carried – see our main Lyme disease pages.

Patients are rarely tested for these other diseases, many of which have symptoms overlapping those of Lyme disease, so how often people are infected in the UK is unknown. Most of these infections respond to the same antibiotic treatment as Lyme disease.  The main tick-borne diseases are  –

Anaplasmosis: sometimes called Human granulocytic anaplasmosis (HGA) is caused by the bacterium Anaplasma phagocytophilum. It tends to cause more fever than Lyme disease and give rise to abnormal liver function tests and low white blood cells and platelets(5). There have been some UK cases, but it is rarely tested for (4). Anaplasmosis responds to the same treatment as for Lyme disease.

Babesiosis: caused by one of three species of Babesia parasite. (5) It infects red blood cells and can cause anaemia, dark urine as well as significant headache, fever and abdominal complaints. Most people have very mild symptoms but older people and those immunocompromised are at more risk of severe disease. First Scottish case reported in 1979 a suspected English case in 1974 and a confirmed case in England in 2020. Because it is thought most people will not need treatment, there may have been many un-diagnosed cases. Babesiosis is treated with specific antibiotics and quinine. See our news item.

Rickettsiosis: caused by species of Rickettsia bacteria and also transmitted by mites (6,7) It can cause a spotty rash, fevers and sometimes a black “eschar”, or scab, at the site of the tick bite. Positive blood tests have been recorded in UK patients. Rickettsia infections respond to the same treatment as for Lyme disease.

Borrelia miyamotoi causes a Lyme-like illness but without an EM rash and with more fever (sometimes coming and going) and headache. In some cases meningitis develops. (10) There have been no reported UK cases yet.

Tick Borne Encephalitis Virus is relatively new to the UK. It was found in a few UK ticks in 2019 and 2 cases have now (Aug 2020) been reported. It causes a few days of ‘flu like symptoms, a gap of some days, then possibly meningitis. (9) Endemic in much of Europe & Asia. A vaccine is available. Read our 2019 news item.

Louping ill virus is endemic to UK upland areas and causes a severe infection of the central nervous system. It is common in sheep, grouse and other animals. (8) Human cases are rare.

All the above except Louping ill are more common in mainland Europe. North America has a different spectrum of tick-borne diseases as well as different ticks so American information can not be extrapolated to the UK.

UK Monitoring of tick-borne diseases. The PHE Tick Surveillance Scheme regularly screens collections of ticks for diseases. The UK Human Animal Infections and Risk Surveillance group (HAIRS) meets every month and issues reports and risk assessments on emerging tick-borne bacteria and viruses in the UK.


  1. Layzell SJ, Bailey D, Peacey M, Nuttall PA. Prevalence of Borrelia burgdorferi and Borrelia miyamotoi in questing Ixodes ricinus ticks from four sites in the UK. Ticks Tick Borne Dis. 2017;9(2):217–24.
  2. Abdullah S, Helps C, Tasker S, Newbury H, Wall R. Prevalence and distribution of Borrelia and Babesia species in ticks feeding on dogs in the U.K. Med Vet Entomol. 2017;
  3. Smith FD, Wall LER. Prevalence of Babesia and Anaplasma in ticks infesting dogs in Great Britain. Vet Parasitol. 2013 Sep 4;
  4. Hagedorn P, Imhoff M, Fischer C, Domingo C, Niedrig M. Human Granulocytic Anaplasmosis Acquired in Scotland 2013. Emerg Infect Dis. 2014;20(6):20–2.
  5. Azagi T, Hoornstra D, Kremer K, Hovius JWR, Sprong H. Evaluation of disease causality of rare ixodes ricinus-borne infections in Europe. Pathogens. 2020;9(2).
  6. Tijsse-Klasen E, Hansford KM, Jahfari S, Phipps P, Sprong H, Medlock JM. Spotted fever group rickettsiae in Dermacentor reticulatus and Haemaphysalis punctata ticks in the UK. Parasit Vectors. 2013 Jan;6(1):212.
  7. Portillo A, Santibáñez S, García-Álvarez L, Palomar AM, Oteo JA. Rickettsioses in Europe. Microbes Infect. 2015;17(11–12):834–8.
  8. Jeffries CL, Mansfield KL, Phipps LP, Wakeley PR, Mearns R, Schock A, et al. Louping ill virus: An endemic tick-borne disease of Great Britain. J Gen Virol. 2014;95(PART 5):1005–14.
  9. Public Health England. Tick-borne encephalitis Epidemiology , diagnosis and prevention.
  10. Henningsson, A.J. et al.  Two Cases of Borrelia miyamotoi Meningitis, Sweden, 2018. Emerg. Infect. Dis. 2019, 25, 1965– 1968, doi:10.3201/eid2510.190416