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Spirochaetes. Presentation Outline. Morphology Organisms Diseases Leptospirosis Lyme disease Syphilis Tests. Spirochete Morphology. Gram negative cell wall often too small to see by light microscopy special stains Spiral morphology distinctive tight coils Motile
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Presentation Outline • Morphology • Organisms • Diseases • Leptospirosis • Lyme disease • Syphilis • Tests
Spirochete Morphology • Gram negative cell wall • often too small to see by light microscopy • special stains • Spiral morphology • distinctive tight coils • Motile • Periplasmic flagella
Spiral bacterium Spirillum volutans
Axial Filament • Between cell wall and cytoplasmic membrane • Attached at either end of cell • Overlap in the centre • constrict at overlap • pulls ends together
Spirochetes:Features • Chemoorganotropic • Range of oxygen requirements • Life style • Free living • host associated
Spirochaete Motility Click on image
Spirochetes: genera • Borrelia (lyme disease) • Brachyspira • Cristispira • Leptonema • Leptospira (Leptospirosis) • Serpulina • Spirochaeta • Treponema (Syphilis)
Leptospira biflexa • free living saprophyte in moist environments • motile, flagella • aerobic • can be grown in 2 weeks
Leptospirosis • Leptospira interrogans • Zoonosis of wild & domestic animals • acquired from urine of infected animals • Dogs, rodents • Portal of entry • broken skin or mucosa • Bacteremia
L. interrogans • Carried by wild and domestic animals • source of human infection • Streams, rivers, moist soil • contaminated by animal urine • Person to person very rare.
Occupational exposure • farmers, slaughter house • workers, veterinarians.
L. interrogans • mild flu like febrile illness • Weil’s disease • renal and hepatic failure • vasculitis • meningitis • myocarditis • death • Penetrate all organs including CNS • Enter through small cuts
Leptospirosis • Febrile illness not clinically distinctive • Acute phase • Leptospiremic phase • incubation 7 -14 days • fever, headache, muscle pain nausea • Immune phase • found in urine • meningitis
Borrelia Relapsing Fevers Lyme Disease
Relapsing Fever • Borrelia recurrentis • Tick borne Relapsing fever • rodents are reservoir • soft shelled ticks • Louse borne Relapsing fever • humans are reservoir • body louse
Borrelia • Easily seen in blood smear • Also confirmed by injecting mouse • blood stream teaming with Borrelia
B.recurrentis • Tick borne relapsing fever is a zoonotic • Clinical evolution: relapsing fever • Serological tests not useful • treatment • tetracycline
Lyme Disease • Lyme, Conneticut USA - spring/fall • Borrelia burgdorfii • reservoir rodents, pets, deer • vector hard shelled ticks • Bite: incubation 3-30 days
Lyme Disease: Early Signs • Erythema chronicum migrans • Erythematous skin lesion • small macule or papule - enlarges to 68 mm. • Malaise, severe fatigue, headache, fever, chills, • chronic neurologic, cardiac rheumatic manifestations.
Lyme Disease: Complications • 1 month or more • myalgia, lymphadenopathy • Up to 2 years • meningitis, encephalitis, peripheral nerve neuropathy. • Cardiac disfunction, myopericarditis.
Lyme Disease: Serology • Immunofluorescence assay • Enzyme-linked immunoabsorbent assay (ELISA) • False positives • other spirochaetes • infectious mononucleosis • autoimmune disease
Lyme Disease:Treatment • tetracycline or penicillin
Stages of Syphilis • Primary • Secondary • Tertiary
Primary syphilis Chancre: painless blister at the site of contact Heals spontaneously even if untreated
Secondary Syphilis • Lesions of secondary syphilis are dispersed over the body • Lesions appear on the cooler parts of the body
Neuronal Syphilis • Treponemes have invaded the nerve and set up a lesion
Break down products of infected cells cardiolipin VDRL, Wasserman Simple, well documented cross reactive eg TB presumtive test Treponemal antigens more expensive more specific confirmatory test Tests for Syphilis
Performance Objectives Key terms, concepts short answers
Epidemiology of ??? • Disease/bacterial factors • Transmission • Who is at risk • Geography/ season • Incidence • Modes of control
Short Answers • Construct a table of the virulence factors associated with ??? and the biological activity of each • Use a series of no more than four diagrams to describe the mechanism of ??? activity • Describe the clinical manifestions ??? • Construct a table listing the common ??? species and the associated human diseases.
Icteric leptospirosis • first stage: 3-7 days - septicemic • 10-30 days - immune • Cultures positive: blood, then CSF, then urine
Icteric leptospirosis • Jaundice, hemorrhage, renal failure, myocarditis • Anicteric described • Best in CSF, blood, and urine culture -- 1st week • Lab test -- slide agglutination • Doxycycline - treatment • Prevention: rodent control
So What • Know importance • #1 communicable disease growing fast • Know how it is spread • Sexual intercourse • skin-skin contact • Know the symptoms • Syphilis can be identified and cured