Severe Leptospirosis Following Heavy Flooding: A Case Series from a Tertiary Hospital in Southern Thailand

Objective: To describe the clinical characteristics, management, and outcomes of patients with severe leptospirosis following heavy flooding.Material and Methods: We conducted a retrospective descriptive case series of six adult patients with polymerase chain reaction (PCR)-confirmed severe leptospirosis admitted to a tertiary hospital in Southern Thailand after a heavy flood. Demographic data, exposure history, clinical presentation, laboratory findings, management, and outcomes were reviewed from medical records.Results: All six patients were adults (median age 41.5 years, range 19–70); five were male. Five patients reported direct floodwater exposure. The incubation period ranged from 1–5 days. Common symptoms were fever and myalgia. Severe manifestations included acute kidney injury (4/6), pulmonary hemorrhage (4/6), shock requiring vasopressors (5/6), and respiratory failure requiring mechanical ventilation (5/6). All cases were PCR-positive for Leptospira. Ceftriaxone was the main antibiotic regimen. One patient died, yielding a case-fatality rate of 16.7%.Conclusion: Severe leptospirosis after heavy flooding can rapidly progress to multiorgan failure, particularly pulmonary and renal involvement. Early recognition and prompt antibiotic therapy with intensive supportive care are crucial to improve outcomes.