Leptospirosis (also known as field fever, rat catcher's yellows, and pretibial fever among others names) is an infection caused by corkscrew-shapedbacteria called Leptospira. Signs and symptoms can range from none to mild such as headaches, muscle pains, and fevers; to severe with bleeding from the lungs or meningitis. If the infection causes the person to turn yellow, have kidney failure and bleeding, it is then known as Weil's disease. If it causes lots of bleeding from the lungs it is known as severe pulmonary haemorrhage syndrome.