Preventive Strategies for Early and Late Complications of Leptospirosis

The goal of this clinical trial is to learn if complement factor I (CFI) works to predict development of complications in participants with leptospirosis. It will also learn if plasma transfusion, hemoperfusion, and extracorporeal membrane oxygenation works to treat participants with leptospirosis. The main questions it aims to answer are: * Does a low level of CFI predict the development of lung damage in participants with leptospirosis? * Does plasma tranfusion lower the chances of participants getting lung damage from leptospirosis? * Does hemoperfusion work to remove harmful materials from the blood of participants with leptospirosis? * Does extracorporeal membrane oxygenation increase the chance of survival in participants with lung damage? Researchers will compare plasma tranfusion and hemoperfusion to conventional therapy (standard of care for leptospirosis, including antibiotics, fluids, and other treatment that the doctor deems necessary) to see if these novel therapies work to treat leptospirosis. Participants will: * Give blood samples for the study of CFI * Receive conventional therapy and/or plasma transfusion for 4 times in 2 days, OR * Receive conventional therapy and/or hemoperfusion for at least 3 days, AND/OR * Receive extracorporeal membrane oxygenation if their condition worsens