Rickettsial Infections
What Are Rickettsial Infections?
Rickettsiae are a group of bacteria that live inside cells and are primarily spread by arthropods — including ticks, fleas, lice, and mites. In the UK, spotted fever group rickettsiae have been detected in Dermacentor reticulatus and Haemaphysalis punctata ticks. Other Rickettsia species are found in ticks in parts of Europe and other regions.
Confirmed human cases in the UK are very rare. Rickettsial infections are better known in warmer parts of Europe and in tropical regions, but awareness is growing as more surveillance is done in the UK.
Examples of distinctive rashes seen in rickettsial diseases. (Image: LymeDisease.org)
How You Get It
Through the bite of an infected tick. In the UK, Rickettsia species have been detected in:
Signs & Symptoms
Symptoms vary depending on the Rickettsia species, but typically include:
- Fever and chills
- Headache
- Muscle and joint aches
- A rash (not always present)
- An eschar (“black spot”) at the bite site in some types
Rickettsia helvetica, the species most commonly found in UK ticks, has been associated with mild febrile illness in continental Europe. More severe rickettsial diseases (e.g. Mediterranean spotted fever) are associated with other species and are primarily a risk for travellers to southern Europe, Africa, or Asia.
Diagnosis & Treatment
Diagnosis requires specialised blood tests. Rickettsial infections respond well to doxycycline antibiotics. If you develop unexplained fever or rash after a tick bite, mention the bite to your GP so they can consider tick-borne infections.
UK Context
While Rickettsia DNA has been detected in UK ticks through research and surveillance, the actual risk of human illness in the UK is currently considered very low. Researchers are working to better understand which species are present, how common they are, and whether they are causing unrecognised illness.
Prevention
- Follow our bite prevention guide.
- Remove ticks promptly.
- Travellers to southern Europe, Africa, or Asia should be aware of regional rickettsial diseases and take tick/flea precautions.