A historical reconstruction of Dr. (later Sir) David Bruce's discovery in 1894 that trypanosome parasites were responsible both for a severe outbreak of cattle wasting disease (ngana) and for the 'fly disease' which was killing the horses of European big game hunters in Zululand. Both conditions were due to infection by trypanosomes transmitted from local game animals to cattle and horses by the bite of the tsetse fly. This video is based on Bruce's own account in his Croonian Lectures to the Royal College of Physicians in 1915 and uses archive film and still photographs as well as dramatic historical reconstruction. With Leon Sinden as David Bruce.