Rickettsial Infections

What Exactly 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 usually associated with warmer parts of Europe and tropical regions, but awareness is growing further North as well.

How Do You Get It?

Through the bite of an infected tick. In the UK, Rickettsia species have been detected in:

• Dermacentor reticulatus
• Haemaphysalis punctata

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 antibiotic regimines. 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 due to lack of public and physician awareness.

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.

References & Further Reading

• GOV.UK — Tick Awareness and Toolkit
• LymeDisease.org — Rickettsial Infections (a US patient-advocacy organisation, not a public health body — included for the patient perspective, not as clinical guidance)
• UKHSA — Spotted fever group rickettsiae in Dermacentor reticulatus and Haemaphysalis punctata ticks in the UK
• CDC — Spotted Fever Rickettsioses (US reference)