What is Lyme disease?

Lyme disease (Lyme borreliosis) is the most common tick-borne infection in the Northern Hemisphere — caused by Borrelia burgdorferi in the Americas and related species (B. afzelii, B. garinii) in Europe. It is transmitted by Ixodes ticks (deer ticks, blacklegged ticks) during feeding. The disease ranges from the easily recognised early EM rash to late manifestations affecting the joints (arthritis), nervous system (Lyme neuroborreliosis) and heart (Lyme carditis). It is highly treatable with antibiotics when diagnosed early.

What does erythema migrans look like?

Erythema migrans (EM) — the early Lyme disease rash — is a slowly expanding, warm, non-itching erythema (redness) centred on the tick bite site. It typically begins as a small red spot 3-30 days after the bite, expanding to ≥5cm over days to weeks. The classic "bull's-eye" pattern (central clearing surrounded by an outer ring) is seen in approximately 20-30% — more commonly, EM is a homogeneous flat red lesion. Multiple EM lesions (secondary to bacteraemia) indicate early disseminated disease. EM is clinical diagnosis — do not wait for serology.

How is Lyme disease treated?

Early localised (EM rash): doxycycline 100mg BD × 10-14 days; alternatives (pregnancy, children): amoxicillin or cefuroxime. Early disseminated (multiple EM, early neuroborreliosis without CSF involvement, mild carditis): doxycycline 100mg BD × 14-21 days. Severe disseminated (meningitis, encephalitis, radiculopathy, advanced carditis/heart block): IV ceftriaxone 2g daily × 14-21 days. Late Lyme arthritis: oral doxycycline or amoxicillin × 28 days; antibiotic-refractory arthritis: IV ceftriaxone × 28 days. All stages respond well to appropriate antibiotic courses — no evidence for prolonged regimens.

What is post-treatment Lyme disease syndrome?

Approximately 10-20% of appropriately treated Lyme disease patients report persistent symptoms 6+ months after completing treatment — fatigue, cognitive difficulties, musculoskeletal pain and poor sleep. This is called post-treatment Lyme disease syndrome (PTLDS). Important: multiple double-blind RCTs have shown that prolonged antibiotic treatment (beyond standard courses) provides no benefit for PTLDS and carries risks (IV antibiotic-associated infection, Clostridium difficile). Management focuses on symptom-targeted rehabilitation, physical therapy, cognitive strategies and occupational therapy.

How can Lyme disease be prevented?

Tick avoidance: wear long-sleeved clothes in endemic areas (light colours to spot ticks); tuck trousers into socks; use DEET-based repellents on skin; permethrin on clothing. Tick checks: inspect the whole body after outdoor activity — pay attention to hairline, groin, axillae, behind knees. Proper tick removal: fine-tipped tweezers, grasp tick as close to skin as possible, pull straight up — do not twist, crush or apply petroleum jelly. Prompt removal within 36-48 hours dramatically reduces transmission risk. Vaccine: Lyme vaccine OspA-based (LYMErix) was withdrawn in 2002; a new bivalent vaccine (VLA15) received FDA approval in 2023 (Valneva/Pfizer partnership) — recommended for high-risk groups in endemic areas.

How does GMJ News cover Lyme disease?

GMJ News covers WHO and ECDC Lyme disease data, erythema migrans recognition, two-tier serology, doxycycline treatment, tick prevention, climate change and tick range expansion, and the PTLDS controversy. Lyme disease is the most common tick-borne infection in the European WHO region — relevant to Georgian tick-borne disease surveillance and PHIG's One Health programme.

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Lyme Disease

GMJ News knowledge hub · last reviewed September 2026 · Georgian Medical Journal

Summary Statistics Glossary GMJ news FAQ Documents Organizations Research

Lyme disease — caused by Borrelia burgdorferi (Americas) and related species (B. afzelii, B. garinii in Europe) and transmitted by Ixodes deer ticks — is the most common tick-borne infection in the Northern Hemisphere, with an estimated 476,000 cases/year in the USA and approximately 200,000 cases/year in Europe (WHO). The pathognomonic erythema migrans rash — a bull's-eye expanding erythema at the tick bite site — occurs in approximately 70-80% of cases and warrants immediate treatment without awaiting serology. Climate change is expanding Ixodes tick habitats northward and to higher altitudes, increasing human exposure.

Key messages

Most common tick-borne infection in Northern Hemisphere

Lyme disease is the most common tick-borne infection in the Northern Hemisphere — with approximately 476,000 cases/year in the USA and approximately 200,000 in Europe. Climate change is expanding Ixodes tick habitats northward (WHO).

Erythema migrans — clinical diagnosis, treat immediately

The pathognomonic erythema migrans (EM) rash — an expanding bull's-eye erythema ≥5cm at the tick bite site — occurs in approximately 70-80% of Lyme cases and warrants immediate antibiotic treatment without waiting for serology.

Three Borrelia species — different clinical profiles

B. burgdorferi (Americas): more arthritis. B. afzelii (Europe): more chronic skin disease (acrodermatitis chronica atrophicans). B. garinii (Europe): more neurological disease. European Lyme disease often has a different clinical course.

Doxycycline is first-line

Doxycycline (100mg BD, 10-21 days) effectively treats early localised and disseminated Lyme disease. IV ceftriaxone is used for severe neurological disease, carditis (heart block) or refractory arthritis.

Tick removal within 36 hours prevents disease

Prompt tick removal within 36-48 hours of attachment dramatically reduces transmission risk (Ixodes ticks typically require 24-48 hours of feeding to transmit Borrelia). Proper removal with fine-tipped tweezers is essential — do not apply heat or petroleum jelly.

Post-treatment Lyme syndrome — controversy

Approximately 10-20% of patients report persistent fatigue, pain and cognitive difficulties lasting 6+ months after treatment (PTLDS). Prolonged antibiotic courses beyond standard treatment show no additional benefit and risk harm — management focuses on symptom-targeted rehabilitation.

Key statistics

476K

estimated Lyme cases/year in USA (CDC)

CDC/WHO

200K

estimated Lyme cases/year in Europe

ECDC/WHO

70-80%

of Lyme patients develop erythema migrans

WHO

36-48hr

tick attachment time for significant Borrelia transmission

WHO/CDC

10-20%

develop post-treatment Lyme disease syndrome (PTLDS)

WHO

2023

year mRNA Lyme vaccine (mRNA-1975) entered Phase 2 trials

Moderna/Pfizer

Lyme disease — clinical stages, timing and manifestations

Source: WHO/IDSA. Most cases present in early localised stage with EM rash; untreated can progress to disseminated and late disease.

Glossary of key terms

Erythema migrans (EM)
WHO/IDSAThe pathognomonic early Lyme rash — an expanding, ring-like (annular) or homogeneously red lesion ≥5cm diameter centred on the tick bite site. Present in approximately 70-80% of early Lyme cases. Clinical diagnosis — begin doxycycline immediately; do not wait for serology (serology is negative in early Lyme). The classic "bull's-eye" (central clearing) is present in minority; homogeneous erythema is more common.

Two-tier serology
WHO/CDC/ECDCStandard Lyme serology: Step 1: EIA or IFA for anti-Borrelia antibodies (sensitive screen). If positive or equivocal: Step 2: Western blot (IgM — early disease; IgG — disseminated/late). A positive two-tier test confirms Lyme disease (but serology can be negative in very early disease, and positive serology without clinical symptoms does not diagnose Lyme disease).

Lyme carditis
WHO/ClinicalCardiac manifestations of early disseminated Lyme — predominantly atrioventricular block (any degree, including complete heart block). Occurs in approximately 1-5% of Lyme disease cases. Presents with palpitations, syncope, dyspnoea. Most resolve with antibiotics; severe (complete heart block, haemodynamic compromise) requires temporary cardiac pacing.

Lyme arthritis
WHO/ClinicalLate Lyme disease arthritis — typically oligoarticular, affecting large joints (predominantly knee), weeks to months after initial infection. Synovial fluid: inflammatory (10,000-100,000 cells, predominantly neutrophils). Treated with oral doxycycline or amoxicillin; IV ceftriaxone for antibiotic-refractory arthritis.

Acrodermatitis chronica atrophicans (ACA)
WHO/European LymeA chronic skin manifestation of late B. afzelii infection (predominantly European) — initially inflammatory (bluish-red skin discolouration, swelling), progressing over months-years to atrophic skin (cigarette paper-thin, with visible vasculature). Treated with doxycycline.

Ixodes tick life cycle
WHO/EntomologyThree-stage life cycle (larva → nymph → adult) over approximately 2 years. Nymphs (May-July) — the most common human-biting stage because they are tiny (poppy seed-size) and bite undetected. Adults (autumn) — more visible, bite less often because humans detect them. Borrelia transmission requires approximately 24-48 hours of tick attachment.