<human>:  How does the disease called ‘gangrene’ spread?
<bot>: Gangrene is a disease that is caused by a lack of blood flow to a part of the body. It is caused by a number of different things, including injury, infection, and vascular disease. Gangrene is a serious condition that can lead to amputation of the affected limb. It is important to seek medical attention immediately if you have any symptoms of gangrene.