Leptospirosis is a bacterial infection caused by Leptospira species, typically transmitted through contact with water, soil, or surfaces contaminated by the urine of infected animals, especially rodents. The bacteria can enter the body through cuts in the skin or through the eyes, nose, or mouth. Symptoms often begin suddenly and may include high fever, headache, muscle aches (particularly in the calves), chills, vomiting, red eyes, and abdominal pain. While many cases are mild, the infection can progress to severe disease involving liver damage (causing jaundice), kidney failure, bleeding disorders, or meningitis. Because symptoms can resemble other febrile illnesses, laboratory testing is used to confirm the diagnosis, particularly in individuals with relevant exposure history.