Background: Leptospirosis is a zoonosis transmitted through urine of infected animals. Symptoms range from mild influenza-like symptoms to severe pulmonary hemorrhagic syndrome (SPHS); the latter are often fatal. The serogroup distribution in Denmark has changed from 1988 to 2012, with Icterohaemorrhagiae and Sejroe now being predominant. Case report: A 45-year-old Danish woman living in an area endemic for Hanta virus, without prior medical history, was admitted because of lower back pain radiating to the left hip, fever, headache, nausea, and malaise. Two weeks before admission she had been bitten by a mouse or a rat. Blood tests revealed raised white cells and CRP, electrolyte imbalances, raised creatinine, low thrombocytes, and a slightly decreased clotting factor (II, VII, and X). Treatment with broad-spectrum intravenous antibiotics and supporting therapy was initiated very quickly. Eight hours after admission she died from respiratory failure where severe hemoptysis was observed. Leptospiral DNA was later detected in a urine sample. Conclusions: This case represents leptospirosis with severe pulmonary hemorrhagic syndrome. In spite of immediate treatment with broad-spectrum antibiotics, the patient died a few hours after hospital admission. ; BACKGROUND Leptospirosis is a zoonosis transmitted through urine of infected animals. Symptoms range from mild influenza-like symptoms to severe pulmonary hemorrhagic syndrome (SPHS); the latter are often fatal. The serogroup distribution in Denmark has changed from 1988 to 2012, with Icterohaemorrhagiae and Sejroe now being predominant. CASE REPORT A 45-year-old Danish woman living in an area endemic for Hanta virus, without prior medical history, was admitted because of lower back pain radiating to the left hip, fever, headache, nausea, and malaise. Two weeks before admission she had been bitten by a mouse or a rat. Blood tests revealed raised white cells and CRP, electrolyte imbalances, raised creatinine, low thrombocytes, and a slightly decreased clotting factor (II, VII, and X). Treatment with broad-spectrum intravenous antibiotics and supporting therapy was initiated very quickly. Eight hours after admission she died from respiratory failure where severe hemoptysis was observed. Leptospiral DNA was later detected in a urine sample. CONCLUSIONS This case represents leptospirosis with severe pulmonary hemorrhagic syndrome. In spite of immediate treatment with broad-spectrum antibiotics, the patient died a few hours after hospital admission.