Leptospirosis and Oropouche fever are two conditions to consider in the differential diagnosis of acute febrile illness. Leptospirosis is an endemic disease, and its severe form has high mortality (Weil’s syndrome). Oropouche fever is an emerging disease and is not usually severe, but with the rise in cases in Brazil since 2023, case reports have been described (1–3). KMOC, a 23-year-old woman, was admitted in Paraty/RJ with asthenia, headache, myalgia, fever, and abdominal pain. She was obese, had hypothyroidism treated with levothyroxine 75 mcg, and no other comorbidities. She reported cleaning her home’s septic pit one week before symptom onset, with the presence of numerous rats. After 3 days she was transferred to another hospital, already with suspected leptospirosis and having received ceftriaxone for 2 days. She arrived hemodynamically unstable, poorly perfused, with peripheral cyanosis, fever of 40°C, macroscopic hematuria, pallor 2+/4+, jaundice 3+/4+, urine output 600 mL/24 h, Glasgow 5, lactate 3.5, hematocrit 33.2%, hemoglobin 11.6%, leukocytes 7,600, platelets 56,000, ALT 122, AST 124, GGT 79.8, ALP 262, total bilirubin 6.3, indirect bilirubin 5.6, direct bilirubin 0.7, creatinine 0.6, urea 41, albumin 2.3, and CRP 116. Chest CT showed bilateral pleural effusion, consolidations, and signs of pulmonary hemorrhage. Intensive supportive care was started, and antimicrobials were changed to piperacillin/tazobactam, azithromycin, and vancomycin. The patient progressed to cardiac arrest and died 3 days after transfer, with bleeding, shock, and hepatitis described as the main complications. Tests sent to a reference laboratory returned positive Oropouche PCR, while other molecular and serologic tests were negative for multiple infectious diseases. Tests sent by the first hospital to a private laboratory returned positive leptospirosis serology (IgM 32.1 and IgG <2), with other tests negative. The patient had suspected severe leptospirosis since hospital admission, with compatible complications and a strong epidemiologic history. Coinfection may be a risk factor for certain complications, but this relationship is not well studied in the literature. To our knowledge, this is the first reported case of Oropouche and leptospirosis coinfection with severe disease and death. The possibility of coinfection should be considered in patients with severe acute febrile illness, and testing for multiple agents, especially arboviruses, should be performed in endemic regions.
Lins et al. (2026) studied this question.