Abstract
Each of two Desert Sheep was infected with 1500 cercariae of Schistosoma mansoni of Northern Sudan. Signs of infection were anorexia, soft faeces, progressive weakness and loss of wool. The sheep were killed 254 and 269 days after infection. The findings were heavy infiltration of the lamina propria with inflammatory cells, numerous ova in the submucosa, hyperplasia of lymphoid tissue, oedema of the mesenteric lymph nodes, and focal pulmonary oedema and congestion. There were egg granulomas, focal necrosis, schistosomal pigment, fatty change, depletion of glycogen and reduction in the activity of adenosine triphosphatase, succinic tetrazolium reductase and glucose-6-phosphatase in the liver. In one sheep 1330 cercariae penetrated and 700 matured to produce males and females in a 5:2 ratio. In the other sheep, about one third of the cercariae penetrated and matured. The ratio of males to females was 3:1.