The corkscrew-shaped bacterium behind Lyme disease, carried by ticks rather than passed between people. Explore its illustrative 3D model, human context, and sources.
PHAC describes B. burgdorferi as a Gram-negative spirochete — a group of highly motile corkscrew-shaped bacteria — measuring 10 to 30 micrometres in length and 0.2 to 0.5 micrometres in width, microaerophilic, oxidase negative and non-spore-forming, with a linear chromosome of about 950 kilobases plus circular and linear plasmids. Transmission is by bites from selected species of ticks, primarily Ixodes scapularis and I. pacificus in North America, and humans are described as dead-end hosts. CDC reports that more than 80,000 Lyme disease cases are reported to it each year, while an estimate using insurance claims suggests 476,000 people are treated for Lyme disease each year.
Risk here is about exposure to infected ticks and about how early the illness is recognised, not about contact with other people — PHAC describes humans as dead-end hosts. CDC reports the erythema migrans rash in approximately 70 to 80 percent of infected people, which means a substantial minority never see the sign most associated with the disease. PHAC’s three-stage description covers early localised, early disseminated and late disease.
Borrelia burgdorferi · A long, thin spirochete with a few loose, irregular waves, distinct from the tight coils of Treponema. Motility structures are internal. This is a species-informed teaching diagram; colours, proportions, envelope spacing and internal detail are illustrative. The model uses muted illustrative colours; stains, colony pigments and microscopy colourization are not natural cell colours. Anatomy is enlarged for phone viewing. Morphology reference: Borrelia burgdorferi · pathogen safety data sheet.
Source check: 2026-09-20. Educational content; independent scientific review remains pending.