The incidence of schistosomiasis in South Central Africa

1. 1. The incidence of schistosomiasis was determined at autopsy in Salisbury Southern Rhodesia. 2. 2. The bladders and rectums from 150 adult Africans were removed in toto and digested in potassium hydroxide, small snips of mucosa having previously been removed and examined microscopically for ova. 3. 3. Of 150 subjects from widely distributed areas of South Central Africa the digested deposit showed 98 per cent. positive for ova of S. haematobium and S. mansoni. Of these, 147 had S. haematobium, 72 had S. mansoni, and 71 had both S. haematobium and S. mansoni. 4. 4. Only one case of pure S. mansoni infestation was found, which does not bear out clinical experience. 5. 5. Evidence is submitted that there must be few unisexual infestations. 6. 6. The high incidence of the disease in South Central Africa is stressed and is far greater than simple microscopical examination of stool and urine would imply. 7. 7. A comparison of rectal and bladder snips with digestion results is also given. In 134 cases showing positive bladder snips for S. haematobium ova, 92 (68·6 per cent.) rectal snips were positive for S. haematobium ova.