• See Also
  1. Spirochete
  • Epidemiology
  1. Worldwide: Common
  2. United States: 100-200/year (underestimated)
    1. Hawaii accounts for 50% of cases
  • Pathophysiology
  1. See Spirochete
  2. Fresh-waterborne Spirochete (Leptospira interrogans, Leptospira biflexa and 14 other species)
    1. Long, thin, aerobic Spirochetes that are tightly wound
    2. Hook-like appendage on one or both ends
  3. Transmission
    1. Passed via infected animals urine (directly or swimming in contaminated water)
      1. Rats (most common)
      2. Livestock (e.g. horses, cattle, sheeps, goats)
      3. Dogs (often asymptomatic)
    2. Leptospira remains viable for months in water and soil (esp. tropical and subtropical climates)
    3. Leptospira penetrate mucus membranes, broken skin and Conjunctiva
  4. Incubation: 2 to 30 days
  5. Mechanism of injury
    1. Small vessel injury (Vasculitis)
  • Risk Factors
  1. Water activity in endemic areas (Hawaii, Malaysia)
  2. Fresh-water related activities (contaminated water or soil exposure)
    1. Farming or gardening
    2. Hiking across streams
    3. Swimming
    4. Rafting
    5. Canoeing
    6. Spelunking
    7. Camping
  3. Occupations
    1. Veterinary workers
    2. Agriculture
    3. Sewage workers
    4. Fishing industry
    5. Flood exposure
  • Findings
  • Symptoms and Signs
  1. Follows 7-12 day incubation
  2. Anicteric Leptospirosis (90% of cases)
    1. Phase 1 (Leptospiremic Phase): Initial septicemic phase (lasts 3-7 days)
      1. Headache
      2. High fever
      3. Myalgia
      4. Calf tenderness
      5. Conjunctivitis
      6. Maculopapular rash
    2. Phase 2 (Immune Phase, follows brief improvement from phase 1)
      1. Aseptic Meningitis
      2. Uveitis
      3. Chorioretinitis
      4. Hematuria
      5. Hepatomegaly
      6. Splenomegaly
      7. Conjunctival injection
  3. Icteric Leptospirosis (Weil's Syndrome, 10% of symptomatic cases, 5-15% mortality)
    1. Much more severe than anicteric form
    2. Fever
    3. Jaundice with Acute Hepatitis
    4. Azotemia with Acute Renal Failure
    5. Mental status changes
    6. Hypotension
    7. Hemorrhagic Vasculitis
    8. Disseminated Intravascular Coagulation (DIC)
  • Labs
  1. Start empiric therapy if Leptospirosis suspected
    1. Do not wait for diagnostic tests
  2. Serology
    1. Acute phase serum 1-2 weeks after illness onset
    2. Convalesent serum 3-4 weeks after illness onset
  3. Culture (Growth may require 16 weeks on special media)
    1. Blood Culture
    2. Urine Culture
    3. Cerebrospinal Fluid Culture
  4. Dark field microscopy
    1. Best Test Sensitivity is flow blood or CSF within the first 7-10 days
    2. After 7 days, urine is best sample
  5. Advanced Testing may be available
    1. Leptospira Antigen urine (ELISA Monoclonal Antibody)
    2. Leptospira PCR (with samples from Serum, CSF or Urine)
  • Management
  1. Start empirical treatment if suspected
    1. Early treatment offers best prognosis
  2. Mild to moderate infection
    1. Doxycycline 100 mg orally twice daily for 7 days (if age >8 years old) OR
    2. Amoxicillin 16 mg/kg up to 500 mg orally three times daily for 7 days OR
    3. Azithromycin 10 mg/kg up to 1 g on day 1, then 5 mg/kg up to 500 mg daily for 2 days
  3. Severe infection (hospitalized)
    1. Penicillin G 100,000 units/kg up to 1.5 MU IV every 6 hours for 7 days or
    2. Ceftriaxone 100 mg/kg up to 2 g IV every 24 hours for 7 days
    3. Alternatively IV Doxycycline may be used if age >8 years old
  • Complications
  1. Meningitis
  2. Hepatitis to Liver Failure
  3. Nephritis to Renal Failure
  • Prevention
  1. Doxyxycline 200 mg once weekly for prophylaxis if high risk of exposure
  2. Infected pet quarantine
    1. Avoid contact with urine of infected pet and disinfect contaminated areas (with household cleaners)
    2. Infected dogs should be walked to urinate away from water bodies and from human frequented areas
  3. Other measures
    1. Consider Vaccination of dog (covers 4 most common Leptospira species)
    2. Keep dogs away from standing water
  • References
  1. (2016) Sanford Guide to Antibiotics, IOS App accessed 4/14/2016
  2. Anderson (2014) Crit Dec Emerg Med 28(7): 11-9
  3. Gladwin, Trattler and Mahan (2014) Clinical Microbiology, Medmaster, Fl, p 137
  4. Tappero in Mandell (2000) Infectious Disease p. 2495
  5. Day (2016) Am Fam Physician 94(10): 794-802 [PubMed]
  6. Joyce (2002) Prim Care 29(4):971-81 [PubMed]
  7. Lo Re (2003) Am Fam Physician 68(7):1343-50 [PubMed]
  8. Perkins (2017) Am Fam Physician 95(9):554-60 [PubMed]