Nagana is a disease caused by the parasite Trypanosoma brucei, which is transmitted primarily by the bite of the tsetse fly. It mainly affects livestock, particularly cattle, leading to symptoms such as fever, weakness, and swelling. The disease can significantly impact agricultural productivity in affected regions, especially in parts of Africa where the tsetse fly is prevalent. In humans, a related form of the disease is known as African sleeping sickness, which is also caused by Trypanosoma brucei but involves different subspecies. Early diagnosis and treatment are crucial for both livestock and humans to prevent severe health complications and economic losses.