This document summarizes information about Borreliosis (Lyme disease). It describes the phylogeny of Borrelia bacteria, noting the 5 pathogenic species that cause Lyme disease. It then discusses the history and identification of Borrelia burgdorferi as the causative agent. The key points of transmission via tick bites and symptoms of erythema migrans rash and late manifestations like acrodermatitis chronica atrophica are highlighted. Diagnosis involves serology tests or direct isolation through staining of the spirochetes.

1. BORRELIOSIS

2. Phylogeny
• Phylum – Spirochete
• Named after French Biologist Amedee Borrel
• 36 known species
• 05 pathogenic :
– B. burgdorferi sensu stricto – Arthitogenic
– B. burgdorferi sensu lato Lyme’s
– B. garinii – Neurogenic
– B. afzelii - Cutaneous manifestations
– B. recurrentis – Relapsing Fever

3. Introduction
• 1900s, manifestation first reported in Europe
– associated it with tick bites (TBD)
• 1975 - outbreak in Lyme, Connecticut - ‘JRA’
• 1982 - Spirochetes from midgut of the black-legged tick
(Ixodes scapularis erst dammimi) and named Borrelia
burgdorferi after American scientist Willy Burgdorfer
• Commonest tick-borne infection (US) - >16000 / yr

4. Structure
• slender helical shaped bacteria
• Gram negative
• Motile
• Extracellular pathogen
• Aerobic or microaerophilic

5. Transmission
• Vector-borne disease – N Am / EU
• Rodents / Deer - black-legged tick (Ixodes scapularis) or
Western black-legged tick (Ixodes pacificus)
• Transmits B. burgdorferi while feeding on an uninfected
host
– the spirochetes are present in the midgut and migrate during
blood feeding to the salivary glands, from which they are
transmitted to the host via saliva.
• B. burgdorferi cannot penetrate intact skin

6. Exposure Risk
• Residential exposure to infected ticks during
property maintenance, recreation, and leisure
activity
• Outdoor occupations
• Forestry
• Landscaping

7. Ixodes sp
• a

8. Life Cycle
• aa

9. Pathogenesis
• Initial Inoculation
• Expression of Osp A / C
• Binding to TLR – 1 / 2
• Immunological Cascade
• Humoral (Ig M / G)
• Complement

10. Clinical Features
• aa
ACA ; BLC

11. Erythema Chronicum
Migrans (ECM)
• 90% develop ECM at the site of inoculation
• 1–36 (average 9) days after the bite
• local spread of the spirochaete  ring formation
EXPANDING @ few cms / wk
• Zone of clearing behind the advancing ring
producing a target-like morphology (BULL’S EYE
LESIONS)
• LAN + Constitutional Symptoms

12. • aa

13. Acrodermatitis Chronica
Atrophica (ACA)
• Syn – Herxheimer’s Disease
• late cutaneous manifestation of dissemination
• 01 or more years after the original infection
• Hands, feet, knees and elbows
• begins as an erythematous plaque, which slowly
enlarges and gradually becomes violaceous and
atrophic (‘tissue paper atrophy’)
• Spirochaetes have occasionally been cultured

14. • aa

15. DDx
• aa

16. DDx

17. Diagnosis
SEROLOGY
AB-based
• ELISA
• Western Blot
AG-based
• NAAT (PCR / bDNA / TMA / NASBA)
DIRECT ISOLATION
Stains (WSS / DIETERLE / GS / WGS )
HPE 17

18. HPE
ECM
• Focal epidermal spongiosis and parakeratosis can be
seen
• Tightly cuffed Dermal perivascular lymphocytic
infiltrate may contain Plasma Cells
ACA
• Epidermal Atrophy
• liquefaction degeneration of the basal layer and
telangiectasia of the papillary dermis
• Diffuse Dermal perivascular lymphocytic infiltrate
containing Plasma Cells
• Warthin–Starry stain identified spirochaetes in 40% of
cases of both morphologies

19. HPE

20. • aa

21. Dr.T.V.Rao MD 21

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