Shigella Group A, Type 1 (S. dysenteriae), was isolated from 18 (35%) of 51 patients with severe dysentery and was considered the etiological agent in those cases. It is thought probable that this organism was also the etiological agent in at least 27 of the 33 cases that did not yield S. dysenteriae from the single stool specimen analyzed in each case. Of the latter 33, 5 yielded S. flexneri and 1 S. boydii. A species of Salmonella was isolated from one of the cases with S. flexneri infection. S. dysenteriae was also isolated from the Uebi Scebelli River. The etiological status of S. flexneri and S. boydii in the cases in which they were found is questionable. No bacterial pathogen was found in any of the 27 cases that did not yield Shigella.
Entamoeba histolytica cysts were detected in both dysenteric and control groups. No trophosoites were noted and this parasite was not considered to be an etiological agent in the present dysentery epidemic. A coprological and serological survey provided evidence of the many other microbial pathogens prevalent in this area.
This epidemic of dysentery due to S. dysenteriae Type 1 is one of the very few studied in Africa.
Formerly, Head Department of Epidemiology and Director of Tropical Medicine, U. S. Naval Medical Research Unit No. 3 (NAMRU-3), Cairo, U. A. R. Present address: 850 Fifth Avenue, New York, N. Y. 10021.
Head, Department of Bacteriology, NAMRU-3.
Laboratory Technician, Department of Epidemiology, NAMRU-3.