Experimental Typhoid Fever Induced in Guinea Pig With In Vivo Prepared B. Typhosus Toxic Product. ∗

Abstract

Since typhoid fever represents a syndrome manifestly accompanied by toxemia, many and varied attempts have been made to obtain the specific toxic moiety from the typhoid bacillus. While certain of these procedures have yielded toxic materials which when injected into animals produce tissue reactions, they are not, as far as ascertained, analogous to the pathological changes occurring in typhoid fever of man.

The toxic material employed in the experiments herein reported was prepared through an in vivo method, i. e., the activities of the living animal body were used to produce in part or set free a toxic portion of the microorganism. By this method peritonitis was first produced in guinea pigs with cultures of B. typhosus and the animals were killed after they had become sick, which was usually within 8 to 12 hours. After coarse filtration this exudate was filtered through a Berkefeld letter N filter. A series of guinea pigs were injected with the filtrate thus prepared, by different routes, some subcutaneously, some intracardially and others intraperitoneally. Several injections were given to each animal of a series at intervals of from 2 to 4 days. Subsequent to each injection, irrespective of the route, a febrile rise and marked leucopenia occurred. (See charts.) Death of the animals usually occurred in from 2 to 4 weeks.

At autopsy the chief gross pathological changes were noted in the intestine, lymph nodes, spleen, liver and kidney. The peritoneal lymph nodes were markedly enlarged and at times hemorrhagic. Peyer's patches and the solitary follicles of the intestinal tract were much swollen and elevated; in some instances they were somewhat reddened and revealed early ulceration. The spleen was increased in size, soft and congested.