chapter 24 chapter 24 spirochetes spirochetes chapter 24 chapter 24 spirochetes spirochetes.

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  • Slide 1
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  • chapter 24 chapter 24 spirochetes spirochetes chapter 24 chapter 24 spirochetes spirochetes
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  • thin-walled, flexible, spiral rods motile through the undulation of axial filaments
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  • Cause disease in human Treponema : Leptospira : Borrelia:
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  • Histology: Treponema pallidum Histology: Treponema pallidum - testis infected rabbit
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  • Treponema pallidum transmission genital placenta 0.1-0.2 x 6-15um; 8-14 small, regular spirals syphilis syphilis
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  • characteristics spirochetes not seen on Gram-stained smear seen only by darkfield microscopy, silver impregnation or immunofluorescence not cultured in vitro
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  • habitat and transmission habitat: the human skin or mucous membranes intimate contact intimate contacttransmission from mother to fetus from mother to fetus across the placenta across the placenta
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  • Pathogenesis Produce no important toxins or emzymes multiplies at site of inoculation spread widely via the blood stream
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  • Early syphilis Primary syphilis: 2-10 weeks, local, nontender ulcer (chancre) Secondary lesions: maculopapular rash or moist papules rich in spirochetes and highly infectious rich in spirochetes and highly infectious 1st & 2nd lesions heal spontaneously 1st & 2nd lesions heal spontaneously some remain latent
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  • I II III
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  • Tertiary syphilis (late phase) Gummas , aortitis , central nervous system involvement, cardiovascular lesions Treponemas are rarely seen, noninfectious
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  • Congenitial syphilis Infected woman fetus Stillbirth Multiple fetal abnormalities
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  • Treatment Penicillin is effective in the treatment of Penicillin is effective in the treatment of all stages
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  • Leptospira interrogans Disease leptospirosis leptospirosis
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  • Leptospira
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  • characteristics characteristics tightly coiled, fine spirochete Not stained, can be seen on dark-field microscopy Grow in bacteriologic media containing serum (Korthoff media)
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  • Habitat and transmission habitat: rats, domestic livestock habitat: rats, domestic livestock transmission: via animal urine---- contaminate water and soil transmission: via animal urine---- contaminate water and soil (human contact contaminated environment) (human contact contaminated environment)
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  • pathogenesis High risk population: peasant, person who fight a flood, or fishing Ingested or pass through mucous membranes or skin Circulate in the blood Multiply in various organs
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  • Clinical findings Initial bacteremic phase: fever, chills and intense headache (conjunctivae congestion, pain of gastrocnemius, (conjunctivae congestion, pain of gastrocnemius, lymphadenectasis) lymphadenectasis) Subsequent immunopathologic phase: meningitis (stiff neck), liver damage (jaundice) and impaired kidney function
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  • diagnosis History of possible exposure Suggestive clinical signs Detect Ab Isolation of leptospiras
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  • Treatment Penicillin G
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  • avoid contact with the contaminated environment vaccination of livestock and pets rat control prevention
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