Surra (from the Marathi sūra, meaning the sound of heavy breathing through nostrils, of imitative origin)[1] is a disease of vertebrate animals. The disease is caused by protozoan trypanosomes, specifically Trypanosoma evansi, of several species which infect the blood of the vertebrate host, causing fever, weakness, and lethargy which lead to weight loss and anemia. In some animals the disease is fatal unless treated.