Leptospira

Leptospira

 

Human leptospirosis is an acute febrile illness that presents with many manifestations and is found worldwide.

Epidemiology

  • Transmission
    • Leptospirosis is a zoonotic disease of worldwide prevalence caused by the spirochete Leptospira interrogans
      • Although wild mammals (e.g., rodents) serve as a primary natural reservoir, domestic animals (dogs, cattle, swine, horses) serve as a major source of human infection
    • Approximately one-half of infections occur from July to October, but cases can occur throughout the year
    • Most often transmission is indirect, by human contact with soil, food or water contaminated by urine from an infected animal
      • Transmission of organism to humans has occurred through contaminated well water, spring water, food-preparation surfaces and by swimming, rafting or kayaking in water sources where livestock have been pastured
      • Certain occupational groups (agriculture, sewer, construction and stock handling) have been found to be at particular risk for leptospirosis

Organism

  • Spirochete
    • Member of the family Spirochaetales which also includes Treponema and Borrelia

Risk Factors

  • Contaminated water
  • Poor sanitation

Clinical Presentation

  • Leptospiremia follows after an 8-12 day incubation period, with a variable clinical course
  • Infection may present:
    • As subclinical and only detectable by serologic means
    • With an influenza-like febrile illness with high fever, chills, rigor, myalgia, abdominal pain, vomiting and diarrhea
    • As severe, life-threatening multi-organ failure
  • Jaundice occurs infrequently in the U.S.; leptospiral meningitis occurs more frequently, accounting for 5-13% of sporadic lymphocytic meningitis cases
  • Kidneys are invariably involved; urine analysis demonstrates leukocytes, erythrocytes, casts and proteinuria

Diagnosis

  • Laboratory Testing
    • Leptospira antibody testing
    • The laboratory diagnosis of leptospirosis is complicated by the fact that the organism is fastidious and slow-growing, occasionally requiring weeks to grow; in this context, serology represents an acceptable alternative that may be more immediate
  • Differential Diagnosis
    • Differential diagnosis includes dengue, malaria, enteric fever, Hantavirus and rickettsial disease

Treatment

  • Treat with antimicrobials
  • Jarisch-Herxheimer reaction (fever, myalgias, headache, tachycardia, hypotension) may occur with initiation of treatment for all spirochetal diseases

See Also