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Lyme Disease medical comic

This comic follows Borrelia burgdorferi from the tick's gut to the skin, nerves, heart and joints. It covers the vector and reservoir, the three clinical stages, the tick-borne co-infections, two-tier testing, treatment and post-exposure prophylaxis, and ends with NEET-PG and USMLE practice cases.

For MBBS, NEET-PG, FMGE, NEXT and USMLE revision.

Lyme disease: what the comic covers

High-yield points

  • Lyme disease is caused by the spirochete Borrelia burgdorferi, carried by Ixodes (blacklegged deer) ticks — mainly the nymph — with the white-footed mouse as reservoir.
  • The tick usually has to stay attached for 36–48 hours, while the bacterium switches from OspA to OspC and moves to the salivary glands.
  • Stage 1 (early localised): erythema migrans, an expanding red rash with central clearing, often with flu-like symptoms; the diagnosis is clinical, as early serology is often negative.
  • Stage 2 (early disseminated): facial nerve palsy (sometimes bilateral), lymphocytic meningitis and radiculitis, and fluctuating AV-nodal heart block.
  • Stage 3 (late): intermittent asymmetric arthritis of large joints, the knee most of all; late neuroborreliosis and acrodermatitis chronica atrophicans.
  • Ixodes ticks can also pass on Babesia microti and Anaplasma phagocytophilum.
  • Serology is two-tier: a screening EIA, then Western blot or a second EIA if positive.
  • Doxycycline is first line; IV ceftriaxone is used for meningitis or high-grade heart block; a single dose of doxycycline within 72 hours can prevent infection after a high-risk bite; watch for a Jarisch–Herxheimer reaction.

Quick questions

Is a blood test needed to diagnose early Lyme disease?

No. Erythema migrans in someone with possible tick exposure is enough to diagnose early Lyme disease, because antibodies may not yet be detectable. Serology helps in later stages.

What heart problem does Lyme disease cause?

Lyme carditis, most often fluctuating atrioventricular block, which can progress to high-grade block. High-grade block is treated with IV ceftriaxone and monitoring.

What is the treatment of Lyme disease?

Oral doxycycline for most early and late cases. IV ceftriaxone is used for Lyme meningitis, severe neurological disease or high-grade heart block.

Is this comic free to read?

The first pages are free to preview. Members read the full comic, and you can sign up free to read one comic in full.

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Topic map: Lyme disease in 7 branches

  1. Organism and tick
    • Borrelia burgdorferi
    • Ixodes ticks, mainly nymphs
    • Reservoir: white-footed mouse
    • Attached 36–48 hours
    • OspA to OspC switch
  2. Stage 1: early localised
  3. Stage 2: early disseminated
  4. Stage 3: late
  5. Testing
  6. Treatment
  7. Prevention

28 points, each linked to its comic page. Guests open the first branch; a free account opens two; Hero and Superhero members open the whole map.

Practice MCQs (15 questions, NEET-PG and USMLE style)

Question 1 (NEET-PG style)

The main reservoir host of Borrelia burgdorferi in nature is the:

  1. White-tailed deer
  2. White-footed mouse
  3. Domestic dog
  4. Brown rat

Answer: B. White-footed mouse

The white-footed mouse (Peromyscus leucopus) is the main reservoir: larval and nymphal Ixodes ticks pick up Borrelia burgdorferi when they feed on infected mice. White-tailed deer are important as the host on which adult ticks feed and mate, keeping tick numbers high, but they do not amplify the bacterium. Humans are accidental, dead-end hosts. Lyme disease is the most common tick-borne illness in the United States.

Question 2 (USMLE style)

A 30-year-old woman returns from a hiking trip in Massachusetts. Nine days later she notices a red patch on her thigh that has grown to 11 cm across, with a clearer centre, and she feels tired, achy and feverish. She does not recall a tick bite. Which organism is the most likely cause?

  1. Rickettsia rickettsii
  2. Treponema pallidum
  3. Ehrlichia chaffeensis
  4. Borrelia burgdorferi
  5. Francisella tularensis

Answer: D. Borrelia burgdorferi

An expanding red rash larger than 5 cm, often with central clearing (erythema migrans), appearing 3 to 30 days (usually 7 to 14) after time outdoors in a tick-endemic area, is the hallmark of early localised Lyme disease caused by Borrelia burgdorferi. Flu-like symptoms ('summer flu') are common, and many patients never notice the bite because nymphal ticks are tiny. Rocky Mountain spotted fever (R. rickettsii) causes a petechial rash starting on the wrists and ankles, and ehrlichiosis usually has no rash.

Practice questions written by Q World Medical Comics. Not affiliated with NBEMS, NBME or the USMLE program.

High-yield flash cards (36 cards)

Causative organism of Lyme disease
Borrelia burgdorferi (sensu stricto in North America; B. afzelii and B. garinii also in Europe and Asia) — a microaerophilic spirochaete
Vector of Lyme disease
Hard ticks of the genus Ixodes — I. scapularis (blacklegged or deer tick) in eastern USA, I. pacificus on the west coast, I. ricinus in Europe; the nymph transmits most infections
Reservoir host and role of deer in Lyme disease
The white-footed mouse (and other small mammals) is the main reservoir; white-tailed deer are not infected but feed adult ticks, keeping tick numbers high

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