August 16, 1933: First day of amoebic dysentery outbreak at the Chicago World’s Fair. American Journal of Public Health editorial. “There are many reasons why the outbreak of amebic dysentery in Chicago in 1933 still holds intense interest. Some of these are practical and some scientific. On the practical side it will be recalled that the Exposition for 1934 opened in May. Already some of the daily papers are asking whether precautions have been taken to make the city safe for visitors, and repeating the charge that the news last year was suppressed. On the scientific side it must be pointed out that, as far as we have been able to determine, this is the first epidemic of the sort which has ever been recorded. The health officers had an entirely new problem to deal with, and there is no question that it took them by surprise, as it did everyone else. The paper read before this Association on October 9, 1933, attracted little attention; so little, in fact, that a prominent officer of the Public Health Service who heard it went back to Washington and did not even mention it. Some days later the report of a physician in Indianapolis that there were 5 or 6 cases of the disease in that city, all traceable to Chicago, gave the first intimation of its seriousness. Following this, on November 25, came from Boston what was probably the first information which showed how widespread the infection was, cases in Canada and elsewhere being reported. There was no official publication from the Board of Health of Chicago, as such, until November 18, though on November 14, the radio was used.
The health authorities of Chicago have been blamed severely for suppression of the news and it has been charged that it was done in order not to scare visitors away from the Exposition.
A careful and what we believe to be an unbiased investigation fails to substantiate such a motive, though the facts are as just stated.
It must be remembered that very few of these cases occurred in Chicago, two having been reported on August 16, the date which the authorities fixed as the beginning of the outbreak. Owing to the period of incubation, which has been fixed by several observers on epidemiological evidence as from 12 to 30 days for the majority of cases, and even longer for others, visitors had arrived home in Canada and various parts of the United States before being taken sick. Doctors have all been taught that amebic dysentery is a tropical disease, and were not looking for it. Various diagnoses, such as appendicitis, colitis, ulcerative colitis, etc., were made. Operations for appendicitis were entirely too frequent, and the evidence shows that the majority of deaths have occurred among those who were operated on under mistaken diagnoses. Up to January 24, 1934, 721 clinical cases of amebic dysentery in 206 cities have been found and traced to Chicago, in addition to which, 1,049 carriers have been found in Chicago. Ninety-four per cent of the cases detected were guests at either Hotel C or A. Hotel A obtained its water from a tank on the roof of Hotel C. This water had been used for cooling and air conditioning purposes before being pumped to the roof. On January 22, a committee met in Chicago for 6 days and heard reports. Their conclusions have entirely changed the picture if they are accepted. In the meantime engineers have studied the situation, and several men who are specialists in the study of tropical diseases have been called upon.
As early as November 22, the hotels incriminated were directed to improve their plumbing arrangements. The Board of Health has had some 15 engineers or technical assistants making an intensive study of the water and sewage systems of the hotels involved. It must be said that they were in a mess. Like Topsy, the system has just “growed,” without noticeable planning. The house engineers have been in the habit of making repairs and additions without notifying the city. The inspection of hotels is not what it should be. Several city departments have inspectional powers, such as the Building Department, Fire Department, License Department, Department of Gas and Electricity, Smoke Inspection Department, Department for the Inspection of Steam Boilers, Department of Public Works, and Board of Health. It would seem that concentration of responsibility might have led to better results. Since the depression and the bankrupting of the city by the former administration, there is a shortage of inspectors, and even new work is scarcely kept up with, much less watching old work, repairs, alterations, etc. The evidence is that two hotels were responsible for 94 per cent of the cases detected. Careful charts have been made showing the dates of registration of the visitors and the dates when their bills were paid, as well as the appearance of the symptoms and the course of the disease as far as possible. If any considerable number of cases have occurred in the city, they have not been detected.
The hotels involved have been ordered to rearrange entirely their plumbing systems and to install new works throughout. The older part of the chief hotel dates back to the time when steel pipe was considered the best material for such work. The sanitary sewer pipes were found to be badly corroded, so that the writer pushed a five cent kitchen fork through the main pipe. Many leaks existed and, in a number of places, wooden plugs now badly rotted had been used to stop holes. Unfortunately, the sanitary sewer which carried some 62 per cent of the load of the hotel passed directly above the tank in which water was refrigerated for the dining rooms and the floors….”
Commentary: When I was an undergraduate, my textbooks referred to treatment methods to remove Entamoeba histolytica from drinking water. I was always confused about this because I had not heard why this pathogen was such a problem. The editorial from the American Journal of Public Health in 1934 reproduced above (almost in its entirety) gives much of the needed detail about the problem. It appears clear that the outbreak was caused by a cross connection between the sewer system and the drinking water system and that it affected two hotels. I particularly like the visual image of pushing a fork through a corroded sewer pipe. Another report noted that some cases of the disease probably occurred as early as June 1933. A total of 98 deaths were attributed to the outbreak.