SHIGELLOSIS IN CYNOMOLGUS MONKEYS (Macaca irus)

Abstract

In seven experiments, thirty-three healthy cynomolgus monkeys that had no dysentery bacilli were administered with 10-20 mg of Shigella flexneri 2a which was isolated from a lesion in the large intenstine of a cynomolgus monkey which died from spontaneous dysentery. These animals were starved for 24 to 32 hours before the administration of the bacilli. Of these animals, 16 developed typical dysentery and remaining 17 were apparently normal. Dysenteric cases excreted a large amount of bloody mucous stool 1-3 days after the administration and the dysenteric diarrhea continued for 2-6 days. The number of S. flexneri 2a in the rectal excreta of dysenteric cases ranged from 107 to 109 for about 7 days after the administration of the bacilli and it decreased with the recovery from diarrhea. In non-dysenteric cases, the number of bacilli remained approximately below 107. Serum agglutinin titer had a trend to rise after several days of experimental infection in both dysenteric and non-dysenteric cases. In dysenteric cases, BSR and WBC definitely increased, whereas S-VC and S-Prot levels declined corresponding to the course of disease. On the other hand, these values remained almost normal in non-dysenteric cases throughout the experiment. The results obtained were discussed from the standpoint to elucidate the identity of the infection of Shigella and the development of bacillary dysentery in cynomolgus monkeys.