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LEPTOSPIROSIS

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spiral-shaped organism with internal flagella. thin, tightly coiled ... in renal tissue (post-mortem) of human patient. LEPTOSPIROSIS. Epidemiologic features ... – PowerPoint PPT presentation

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Title: LEPTOSPIROSIS


1
LEPTOSPIROSIS
  • Other disease names
  • Weil disease, hemorrhagic jaundice
  • Causative organism Leptospira interrogans
  • serovars (300 serologic variants)
  • icterohaermorrhagiae (rats)
  • pomona (swine)
  • canicola (canine)
  • autumnalis (raccoons)
  • bratislava (swine)
  • hardjo (cattle)
  • grippotyphosa (cattle)

2
LEPTOSPIROSIS
  • Microbiological features
  • flexible, gram-negative spirochete
  • spiral-shaped organism with internal flagella
  • thin, tightly coiled
  • unique flexuous-type motility

3
LEPTOSPIROSIS
  • EM of Leptospira interrogans (bar0.5?m)

4
LEPTOSPIROSIS
5
LEPTOSPIROSIS
  • Microbiological features
  • readily cultivated, simple nutrient requirements
  • growth in 12 hours at 30ºC, pH 7.4
  • distinguishing features
  • 3-5 layer outer membrane
  • two internal flagella (periplasmic), extending
    from each end of the cell affords better
    motility in viscous environments than with
    external flagella

6
LEPTOSPIROSIS
  • Microbiological features

Immunostain organisms and granular forms of
antigen in renal tissue (post-mortem) of human
patient
7
LEPTOSPIROSIS
  • Epidemiologic features
  • ubiquitous worldwide, especially tropical regions
  • vehicle of transmission leptospiruric urine
  • reservoir wild and domestic animals
    leptospires isolated from gt160 mammalian species
    in temperate zone
  • rodents can shed organisms in urine for lifetime
  • domestic animals important source of infection
    for humans

8
LEPTOSPIROSIS
  • Epidemiologic features
  • transmission direct or indirect by contact with
    infected urine or urine contaminated soil or
    water
  • direct person-person transmission rare
  • soil can remain contaminated for up to two weeks
  • has been reported to have been transmitted from
    infected mother to infant by breast-feeding
  • most cases during summer and fall
  • Case Fatality Rate low but increases with
    advancing age, can be up to 20in individuals
    with jaundice and kidney damage

9
LEPTOSPIROSIS
  • Clinical features
  • incubation period 7-14 days
  • biphasic
  • commonly involves CNS, kidneys, and liver
  • often misdiagnosed as hepatitis or meningitis
  • petechial rash, morbilliform or urticarial in
    appearance - in 10-30of cases within first 2
    days, sometimes pruritic

10
LEPTOSPIROSIS
  • Clinical features
  • acute leptospiremia phase
  • abrupt onset of fever
  • severe headache
  • muscle pain
  • nausea
  • jaundice in more severe cases
  • symptoms persist for up to 7 days

11
LEPTOSPIROSIS
  • Clinical features
  • immune leptospiruric phase
  • occurs after asymptomatic periods of several days
  • antibodies present
  • spirochetes no longer present in bloodstream
  • leptospiral organisms shed in the urine for
    various periods depending on host

12
LEPTOSPIROSIS
  • Clinical features
  • immune leptospiruric phase
  • manifested by
  • fever of shorter duration than acute phase
  • CNS signs (meningitis)
  • more severe form associated with serovar
    icterohaemorrhagiae and is called Weils disease

13
LEPTOSPIROSIS
  • Clinical features
  • mucosa and broken skin most likely route of
    infection
  • multiply in convoluted tubules of kidney (hence
    shed in urine)
  • may persist for weeks to months

14
LEPTOSPIROSIS
  • Pathogenesis
  • Generalized infection (leptospiremia) upon entry,
    but no lesion at site of entry
  • Host response
  • Leptospiricidal
  • Humoral antibody formation
  • Complement
  • Rapid elimination from all except
  • Brain slow growth
  • Eyes slow growth
  • Kidneys shed for weeks to months (urine)

15
LEPTOSPIROSIS
  • Pathogenesis
  • Virulent strains more resistant to
    antibody-complement system
  • Cell-mediated immunity not effective
  • Immunity serotype specific, long-lasting
  • Survival likely due to ineffectiveness of
    Ab-Complement system in convoluted tubules
  • Host can be seronegative shedders due to lack of
    antigenic stimulation

16
LEPTOSPIROSIS
  • Pathogenesis
  • Mechanism unresolved not related to toxin
    formation (endo-, exo-)
  • marked contrast between functional impairment and
    histologic lesions, suggesting damage primarily
    at subcellular level
  • severe infections cause progressive impairment of
    renal and hepatic function but minimal tissue
    damage normal function restored when infection
    clears
  • renal failure most common cause of death

17
LEPTOSPIROSIS
  • Diagnosis
  • demonstration of organisms isolated from blood or
    CSF in first 7 days
  • serology
  • rising titers (MAT - microscopic agglutination
    test)
  • IFA
  • ELISA

18
LEPTOSPIROSIS
  • Prevention and control
  • treatment with antibiotics (penicillin and
    doxycycline) within first week of signs, not
    recommended after acute phase
  • education
  • avoid swimming in potentially contaminated pools
  • protective clothing and shoes should be worn when
    swimming in areas likely to be contaminated

19
LEPTOSPIROSIS
  • Prevention and control
  • reduction of prevalence in animal reservoirs
  • vaccination of pets and livestock prevents
    illness but not necessarily infection and
    shedding must contain dominant local strains
  • rodent control
  • vaccination in humans not recommended
  • prophylactic antibiotic use (Doxycycline) in
    military personnel training in certain tropical
    areas

20
LEPTOSPIROSIS
  • Recent outbreak
  • outbreak of acute febrile illness among athletes
    from 44 states and 7 countries among 110 of 1194
    participants (9) in triathlons that took place
    in Springfield, IL (6/21/98) and Madison, WI
    (7/5/98)
  • Leptospirosis cause of illness in participants
    and other persons exposed to Lake Springfield
  • high titers to serovars grippotyphosa,
    bratislava, djasiman

21
LEPTOSPIROSIS
  • Recent outbreak
  • individuals only participating in Madison event
    had milder illness, no serologic evidence of
    leptospirosis
  • attack rate 11 IL only 5WI only 7both
  • all 23 hospitalized participated in IL triathlon

22
LEPTOSPIROSIS
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