TYPHOID FEVER (from Gk. rvo((171c, ty phndes, delirious, from t yphos, stupor, mist, vapor. smoke. from 1-136eo., typhrin, to smoke: connected with Skt. dhapa, smoke) or ENTERIC FEVER. A specific disease. infectious chiefly or entirely through the excretions. having a febrile period of about three weeks, and char acterized by ulceration of the intestinal lymph follicles, swelling of spleen and mesenteric glands, and parenchymatous changes in many organs.
'Typhoid fever is due to the presence in the body and to the effects upon the body-tissues of a specific micro-organism known as the typhoid bacillus, or bacillus typhosus. This is a small bacillus with rounded ends about two micro millimeters in length and about one-third as broad. lt is motile and grows at room tempera ture on the ordinary culture media, preferably in the presence of air or oxygen, but capable of life without. (See Plate of DISEASE GERAts.) Whether growing in the body or on artifi cial culture media, the bacillus produces a poisonous substance known as typhotoxin, be longing to the same general class as the toxins of diphtheria, tetanus, etc. During typhoid fever the bacillus is found regularly in the intestinal and mesenteric lymph nodes and as a rule in the spleen, In the early stage of the disease, when the nodes are simply enlarged, few or no bacilli are present in the bowel evacuations. Later, when ulceration of the nodules has occurred, the bacilli are usually found in the stools. In urine and bile it is quite common to find the typhoid bacillus, and in these secretions they may per sist long after the passage of the fever, thus furnishing possible sources of infection long after the danger is supposed to have passed. Typhoid bacilli have also been reported in the blood, lungs, pleura, liver, kidney, uterus, and in other organs in which typhoid lesions occur: also in ty phoid serous exudates and in the heart in ty phoid endometritis.
Contraction of typhoid fever is believed to be always caused by the taking of the bacilli into the mouth and thence into the intestine. Food and drink are usually the vehicles which serve for the entrance of the bacillus, water and milk being probably the most frequent sources c' in fection. The latter is especially dangerous from the fact that. the typhoid bacillus not only lives
hut multiplies in it. Water and milk, however, are only dangerous when they actually contain the typhoid bacilli which have entered into them from the excretions of typhoid patients.
The initial seat of activity of the typhoid bacillus is undoubtedly in the intestines. Here the bacillus first sets up a catarrhal inflamma tion of the mucous membrane. This is followed by the most characteristic lesion of typhoid.
namely, inflammation of the intestinal lymph nodes. Both solitary nodules and Peyer's patches are affected, although it is in the latter that the changes are usually most marked. There is first congestion of the nodule and of the surrounding tissues, then increase in the size of the nodule.
This increase in size of the nodule appears to be due to a proliferation of its cellular elements. Thus there is more or less extensive increase in number of the lymphoid cells and of the endothe lial cells which line the lymph-sinuses. When the inflammation is severe it may extend not only peripherally to the tissues laterally adjacent, but also into the deeper tissues of the intestinal walls involving the muscular and serous coats.
These changes are apparently due to the pres ence in and effects upon the nodules of the ty phoid bacillus. Such inflamed nodules may un dergo resolution. The results of the inflamma tion may be absorbed or east off, or both, and the nodules return to their normal condition. On the other hand, in the more severe grades of the infection, the nodules. instead of undergoing such early repair, go on to necrosis and to the formation of the so-called typhoid ulcers. These ulcers are formed in Peyer's patches, increase in size, and discharge info the intestines. (See PEYER'S GLAND.) Not infrequently they open up blood vessels of considerable size and thus cause one of the gravest accidents of typhoid fever, namely intestinal hemorrhage. Or an ulcer may eat its way through the muscular and serous coats and, opening into the peritoneum, produce what is known as a `perforation."This, probably the gravest accident of typhoid, allows bacteria and intestinal contents to soil the peri toneum and leads frequently to the setting up of a general and rapidly fatal peritonitis.