Spirochetes-2/2
Leptospira & Borrelia
Key words
• Borrelia
– Vincent’s angina
– Recurrent fever
– Lyme Disease
• Ixodide tick
• Leptospira
– L. icterohaemorrhagiae
• erythema chronicum migrans
• Weil’ disease (leptospirosis)
– Transmission - urine of rats
B.vincenti
• Normal mouth commensal
• May give rise to ulcerative
gingivostomatitis or
oropharyngitis (Vincent’s
angina) during malnutrition
or viral infections
• B. vincenti always associated
with fusiform bacilli –
fusospirochetosis
• Diagnosis – gram staining of
exudates
• Treatment – Penicillin
Borrelia burgdorferi and
Lyme disease
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B. burgdorferi
• Causes Lyme disease, transmitted by the bite
of Ixodid ticks (deer tick)
• Characteristic rash – erythema chronicum
migrans
• Diagnosis – culture, serological tests
• Treatment – Pen, tetracyclines,
cephalosporins in early stages.
– Late stage – Antibiotics ineffective.
Lyme disease - symptoms
• bacteremia
– acute
• arthritis
• cardiac
• neurologic
– chronic
* weeks, months later
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Diagnosis
• serum antibodies to B. burgdorferi.
• laboratory strains
– grow extremely slowly
– tissue culture media
– not bacteriological media
• patient body fluids/tissue sample
– almost never growth
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A physicians dilemma
• acute
– responds to antibiotic
–antibodies not detectable
• late diagnosis
– not curable
– antibodies detectable
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Lyme Disease -etiology
• reactive arthritis similar to
– Reiter's syndrome
– rheumatic fever
• resembles rheumatoid arthritis.
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Relapsing fever
• transmission
–tick-B. hermsii
* rodent, primary host
– lice-B. recurrentis
* human, primary host
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“Relapsing” fever
• immune response develops
– disease relapses
• new antigens expressed
– no immunity
– disease reappears
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Diagnosis
• no culture
• no serological test
• detected - blood smear
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Leptospirosis
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Leptospira
•
Very thin, delicate spirochetes with hooked
ends
•
2 species are recognised:
1. L. interrogans – include human pathogenic
serogroups: L.icterohaemorrhagiae (rats are the
reservoir)
2. L. biflexa – saprophytic, mainly found in surface
water.
Laboratory characteristics
• Morphology – stained with Giemsa/ silver
impregnation, hooked ends resemble umbrella
handles
• Culture – media (semi solid/ liquid) enriched with
rabbit serum - Fletcher’s medium
• Pathogenicity – causes Weil’ disease
(leptospirosis)
Weil’s disease
• Transmission - Leptospires in water
contaminated by the urine of rats; enters the
body through cuts or abrasions on the skin or
through intact mucosa of mouth, nose or
conjunctiva
• Incubation period – about 10 days (2 to 26)
• Mild fever to severe or fatal illness with
hepatorenal damage
• Fever, rigors, headache, vomiting, icterus,
purpuric hemorrhages
Diagnosis
• Examination of blood – 1st week only
• Urine – 2nd week of disease, should be
examined immediately after voiding
• Serology – Abs appear by the end of 1st week
& increase till 4th week of disease.
Treatment
• Should be started early in disease
• Penicillin I.V., Tetracyclines