Borrelia by aseem
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Transcript of Borrelia by aseem
BORRELIOSIS
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
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
Structure
• slender helical shaped bacteria• Gram negative• Motile • Extracellular pathogen• Aerobic or microaerophilic
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
Exposure Risk
• Residential exposure to infected ticks during property maintenance, recreation, and leisure activity
• Outdoor occupations• Forestry• Landscaping
Ixodes sp
• a
Life Cycle
• aa
Pathogenesis
• Initial Inoculation• Expression of Osp A / C• Binding to TLR – 1 / 2• Immunological Cascade• Humoral (Ig M / G)• Complement
Clinical Features
• aa
ACA ; BLC
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
• aa
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
• aa
DDx
• aa
DDx
17
Diagnosis
SEROLOGY
AB-based • ELISA• Western Blot
AG-based• NAAT (PCR / bDNA / TMA / NASBA)
DIRECT ISOLATION
Stains (WSS / DIETERLE / GS / WGS )HPE
HPE
ECM• Focal epidermal spongiosis and parakeratosis can be seen• Tightly cuffed Dermal perivascular lymphocytic infiltrate
may contain Plasma CellsACA• 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
HPE
• aa
Dr.T.V.Rao MD 21
THANK YOU