Typical paratyphoid outbreaks.—Kaensche[64] describes an outbreak at Breslau involving over eighty persons in which chopped beef was apparently the bearer of infection. The animal from which the meat came had been ill with severe diarrhea and high fever and was slaughtered as an emergency measure (notgeschlachtet). On examination a pathological condition of the liver and other organs was noted by a veterinarian who declared the meat unfit for use and ordered it destroyed. It was, however, stolen, carried secretly to Breslau, and portions of it were distributed to different sausage-makers, who sold it for the most part as hamburger steak (Hackfleisch). The meat itself presented nothing abnormal in color, odor, or consistency. Nevertheless, illness followed in some cases after the use of very small portions. With some of those affected the symptoms were very severe, but there were no deaths. Bacilli of the Bacillus enteritidis type were isolated from the meat.
A large and unusually severe outbreak reported by McWeeney[65] occurred in November, 1908, among the inmates of an industrial school for girls at Limerick, Ireland. There were 73 cases with 9 deaths out of the total number of 197 pupils. The brunt of the attack fell on the first or Senior class comprising 67 girls between the ages of thirteen and seventeen. Out of 55 girls belonging to this class who partook of beef stew for dinner 53 sickened, and 8 of these died. One of the two who were not affected ate the gravy and potatoes but not the beef. Some of the implicated beef was also eaten as cold meat by girls in some of the other classes, and also caused illness. Part of the meat had been eaten previously without producing any ill effects. "The escape of those who partook of portions of the same carcass on October 27 and 29 [five days earlier] may be accounted for either by unequal distribution of the virus, or by thorough cooking which destroyed it. Some of the infective material must, however, have escaped the roasting of the 29th, and, multiplying rapidly, have rendered the whole piece intensely toxic and infective during the five days that elapsed before the fatal Tuesday when it was finally consumed." The animal from which the fore quarter of the beef was taken had been privately slaughtered by a local butcher. No reliable information could be obtained about the condition of the calf at, or slightly prior to, slaughter. The meat, however, was sold at so low a price that it was evidently not regarded as of prime quality. In this outbreak the agglutination reactions of the blood of the patients and the characteristics of the bacilli isolated showed the infection to be due to a typical strain of Bacillus enteritidis.
An epidemic of food poisoning occurred in July, 1915, at and near Westerly, Rhode Island.[66] The outbreak was characterized by the usual symptoms of acute gastro-enteritis, and followed the eating of pie which was obtained at a restaurant in Westerly. All the circumstances of the outbreak showed that a particular batch of pies was responsible. About sixty persons were made seriously ill and four died. There was no unusual taste or odor to the pies to excite suspicion. The symptoms followed the eating of various kinds of pie: custard, squash, lemon, chocolate, apple, etc., that had been made with the same pie-crust mixture. Bacillus paratyphosus B was isolated from samples of pie that were examined. No definite clue was obtained as to the exact source of infection of the pie mixture. It is possible that the pie became infected in the restaurant through the agency of a paratyphoid-carrier, but since there had been no change in the personnel of the restaurant for several months, this explanation is largely conjectural. Possibly some ingredient of animal origin was primarily infected.
General characters of paratyphoid infection.—The symptoms of paratyphoid food infection are varied. As a rule the first signs of trouble appear within six to twelve hours after eating, but sometimes they may come on within half an hour, or they may not appear until after twenty-four to forty-eight hours. Gastro-intestinal irritation is practically always present, and may take the form of a mild "indigestion" or slight diarrhea or may be of great severity accompanied with agonizing abdominal pain. Fever is usual, but is generally not very high. Recovery may occur quickly, so that within two or three days the patient regains his normal state, or it may be very slow, so that the effects of the attack linger for weeks or months.
Investigators have noted the occurrence of at least two clinical types of paratyphoid infection, the commoner gastro-intestinal type just described and a second type resembling typhoid fever very closely, and occasionally not to be distinguished from it except by careful bacterial examination. It is not yet clear how these two clinical varieties are related to the amount and nature of the infecting food material. No difference in the type of paratyphoid bacillus has been observed to be associated with the difference in clinical manifestation. Possibly the amount of toxin present in the food eaten as well as the number of bacilli may exercise some influence. The individual idiosyncrasy of the patient doubtless plays a part.
While there is still some uncertainty about particular features of paratyphoid infection, a few significant facts have been clearly established: (1) Certain articles of diet are much more commonly associated than others with this type of food poisoning. The majority of recorded outbreaks are connected with the use of meat, milk, fish, and other protein foods. Vegetables and cereals have been less commonly implicated, fruits rarely. (2) In many, though not all, of the cases of paratyphoid meat poisoning it has been demonstrated that the meat concerned has been derived from an animal slaughtered while ailing (notgeschlachtet, to use the expressive German term). There seems reason to believe that in such an animal, "killed to save its life," the specific paratyphoid germ is present as an infection before death. Milk also has caused paratyphoid poisoning and in certain of these cases has been found to be derived from a cow suffering from enteritis or some other disorder. (3) There is evidence that originally wholesome food may become infected with paratyphoid bacilli during the process of preparation or serving in precisely the same way that it may become infected with typhoid bacilli; the handling of the food by a paratyphoid-carrier is commonly responsible for this. In a few instances the disease is passed on from case to case, but this mode of infection seems exceedingly rare and is not nearly so frequent as "contact" infection in typhoid. (4) The majority of paratyphoid outbreaks are associated with the use of uncooked or partly cooked food. A selective action is often manifested, those persons who have eaten the incriminated food substance raw or imperfectly cooked being most seriously affected, while those who have partaken of the same food after cooking remain exempt.
Fig. 6.—Bacillus enteritidis, Gärtner; pure culture; Van Ermengem preparation. (Kolle and Wassermann.)
The discovery of the connection of paratyphoid bacilli with meat poisoning dates from the investigation by Gärtner,[67] in 1888, of a meat poisoning outbreak in Frankenhausen, a small town in Germany. This epidemic was traced to the use of meat from a cow that was slaughtered because she was ill with a severe enteritis. Fifty-eight persons were affected in varying grades of severity; the attack resulted fatally in one young workman who ate about eight hundred grams of raw meat. Gärtner isolated from the spleen of the fatal case and also from the flesh and intestines of the cow a bacillus to which he gave the name B. enteritidis. Inoculation experiments showed it to be pathogenic for a number of animal species. Bacilli with similar characters have since been isolated in a number of other meat poisoning epidemics in Germany, Belgium, France, and England. One well-studied instance of food poisoning due to the paratyphoid bacillus has been reported in the United States.[68]