Healthcare Workers

Symptoms and Clinical Features

  • Fever, headache, chills, muscle aches, vomiting, nausea, diarrhea, abdominal pain, cough, conjunctival suffusion, jaundice, and sometimes rash.
  • Incubation period: 5-14 days with a range of 2-30 days.
  • Untreated patients could develop kidney damage, meningitis, liver failure, respiratory distress, and in some cases, may die.

Etiologic Agent

  • Leptospires are long, thin, motile spirochetes
  • Spreads in the urine of animal hosts, survives for weeks to months in fresh water and wet soil in warm areas
  • Leptospiral serovars and species can vary by region
  • Classified into over 300 pathogenic serovars based on antigenic properties. However, antigenic properties are not a predictor of species designation.


  • Early treatment may decrease the severity and duration of disease.
  • In patients with a high clinical suspicion of leptospirosis, initiating antibiotic treatment as soon as possible without waiting for laboratory results is recommended.
  • For patients with mild symptoms, doxycycline is the drug of choice (100 mg orally, twice daily), if not contraindicated. Other options include azithromycin (500 mg orally, once daily), ampicillin (500-750 mg orally, every 6 hours), amoxicillin (500 mg orally, every 6 hours).
  • For patients with severe disease, IV penicillin is the drug of choice (1.5 MU IV, every 6 hours), and ceftriaxone (1 g IV, every 24 hours) can be equally effective.


Leptospirosis is a nationally notifiable condition. The case report form is available in English and Spanish as a fillable PDF that can be completed electronically or can be printed and done by hand. Completed forms can be emailed, faxed, or mailed to CDC.

Incidence and Trends

  • An estimated 1 million cases occur globally each year, resulting in nearly 60,000 deaths.
  • In the United States, about 50% of annual cases are reported from Puerto Rico.
  • Cases of leptospirosis can increase after hurricanes or flooding when people may have to wade through contaminated water or use it for drinking or bathing.
  • Occurring mostly in tropical and subtropical climates, leptospirosis is among the leading zoonotic disease causes of illness worldwide. Health experts believe leptospirosis is underdiagnosed and underreported; true numbers are likely higher.

Laboratory Submissions

Find out more about laboratory submissions by visiting Bacterial Special Pathogens Branch Laboratory Submissions.