It is also possible to become infected through rodent bites and drinking contaminated water. The mild form of the disease is known as leptospirosis. If the bacteria infect other organs of the body, such as the kidneys, heart, liver, lungs, or brain, it can lead to a more severe disease.t is also possible to become infected through rodent bites and drinking contaminated water. The mild form of the disease is known as leptospirosis. If the bacteria infect other organs of the body, such as the kidneys, heart, liver, lungs, or brain, it can lead to a more severe disease.