LEPTOSPIROSIS

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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)

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LEPTOSPIROSIS

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

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LEPTOSPIROSIS

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

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LEPTOSPIROSIS
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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

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LEPTOSPIROSIS

• Microbiological features

Immunostain organisms and granular forms of
antigen in renal tissue (post-mortem) of human
patient
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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

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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

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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

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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

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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

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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

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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

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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)

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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

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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

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LEPTOSPIROSIS

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

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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

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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

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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

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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

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LEPTOSPIROSIS