What is the treatment guideline for possible leptospirosis exposure?

Treatment Guidelines for Possible Leptospirosis Exposure

Treatment should be initiated upon suspicion of leptospirosis exposure, even before confirmatory diagnosis, with penicillin or tetracycline antibiotics which are effective during the bacteraemic phase. 1

Exposure Risk Assessment

Leptospirosis exposure typically occurs through:

• Direct contact with urine from infected animals (particularly rats, but also dogs, cattle, and other domestic/wild animals)
• Contact with urine-contaminated water
• High-risk activities including:
  • Recreational water sports (swimming, rafting, kayaking)
  • Occupational animal or water exposure
  • Exposure during flooding events 1

Treatment Protocol

For Asymptomatic Exposure (Post-exposure Prophylaxis)

• Doxycycline 200mg orally as a single dose within 24-72 hours of high-risk exposure
• Alternative: Amoxicillin 500mg three times daily for 3-5 days

For Symptomatic Patients with Mild Disease

• Doxycycline 100mg orally twice daily for 7 days
• Alternative: Amoxicillin 500mg three times daily for 7 days 1, 2

For Moderate to Severe Disease

• Intravenous penicillin G 1.5 million units every 6 hours
• Alternative: Ceftriaxone 1-2g daily intravenously
• Duration: 7-10 days 1

Clinical Presentation Requiring Urgent Treatment

Leptospirosis follows a biphasic course:

1. Initial bacteraemic phase (4-7 days): Flu-like symptoms
2. Immune phase (1-3 days later): Characterized by fever, myalgia (especially calves), hepatorenal syndrome, and hemorrhage

Key symptoms requiring immediate treatment:

• Fever with myalgia
• Conjunctival suffusion (highly suggestive)
• Signs of Weil's disease (jaundice, renal failure, hemorrhage)
• Pulmonary hemorrhage (severe complication with >50% fatality) 1, 3

Diagnostic Approach

While treatment should begin on clinical suspicion, diagnostic workup includes:

• Serological testing (IgM ELISA) - earliest positives appear 6-10 days after symptom onset
• Blood cultures (within first 5 days, before antibiotics)
• Microscopic agglutination test (MAT) for confirmation
• Urinalysis (may show proteinuria and hematuria) 1

Important Considerations

• Early treatment is crucial - mortality increases with delayed therapy
• Patients with jaundice may become very unwell despite therapy and may require renal or liver support
• Person-to-person transmission is rare; no restrictions from contact sports are necessary 1
• While a systematic review showed no benefit for antibiotic treatment in established leptospirosis, most infectious disease specialists continue to recommend antibiotics 1
• The severe pulmonary hemorrhagic form has a high fatality rate and requires intensive supportive care 3

Prevention Measures

For those at high risk of exposure:

• Avoid direct contact with potentially contaminated water
• Use protective clothing when exposure cannot be avoided
• Consider doxycycline prophylaxis before high-risk activities
• Prompt washing after potential exposure 1