Sanitation in Panama

by William Crawford Gorgas

Dr. Reed then announced that he would disinfect the room so that it would no longer give yellow fever. When it was prepared, he again placed a non-immune in each room, left them there for several days, and they remained perfectly well. He explained that he disinfected the room by simply catching all the stegomyia mosquitoes which he had formerly liberated in the room.

This demonstration made a very profound impression. Many, however, still urged that while it was evident that the female stegomyia mosquito could convey yellow fever, it was equally evident from the history of epidemics of this disease that it could be and was generally conveyed in other ways, such as soiled clothing, bedding, the bodies of yellow-fever dead, persons sick of the disease, etc.

Dr. Reed had a small house built, made almost air-tight and with scarcely any ventilation. This building was known as the infected-clothing building, and was purposely so constructed as to exclude anything like efficient ventilation. It was placed on the opposite side of a small valley, about eighty yards from the infected mosquito building, and they were both about seventy-five yards distant from the camp proper. Both houses were provided with wire screen windows and double screen doors, so that mosquitoes could be kept without or within the building, as the experimenter might desire.

In this building he placed material obtained from Las Animas, the yellow-fever hospital of the Health Department of Havana; mattresses on which yellow-fever patients had died, soiled by their excreta and discharges; sheets, pillows and pillow-cases stained with black vomit; the pajamas which patients had worn at the time of their death. It was Dr. Reed’s desire to have this material infected if it were possible to become infected in this way. Dr. John W. Ross, the superintendent of Las Animas Hospital, therefore gave the matter his personal attention, saw to the packing of this material in chests for transportation to Camp Lazear, and before the chests were closed, had basins of black vomit and other excreta from yellow-fever patients poured over the contents of the chest. If there were any possibility of such material becoming infected, infection certainly would have followed such procedure.

Dr. Reed had this material opened up and spread out in the close room I have described. He called for volunteers to sleep in this room. Dr. R. P. Cook of the Army, and several soldiers quickly responded. These men put on the pajamas soiled as described, and slept on the mattresses and bed clothing soiled beyond description. For a period of twenty days they spent the nights in this building, but for the sake of general health were allowed to go out during the day. All the men remained perfectly well, and no case of yellow fever was developed from such exposure.

This set of experiments was generally accepted as proving that yellow fever was conveyed from man to man by the mosquito alone, and that it was not transmitted in any other way. A great many persons, however, were still skeptical. The experimental camp had been named “Lazear” in memory of Dr. Lazear, a member of the Board, who had died a few months before of yellow fever, contracted while prosecuting this work.

The Board then took the blood of a yellow-fever patient in the first three days of his sickness, and injected it with a hypodermic syringe into a non-immune. He promptly developed yellow fever. This proved that the blood of a patient suffering from this disease could transmit yellow fever without passing through the body of the mosquito. From this experiment of injecting the blood directly from one person into another it was argued that it might not be a yellow-fever parasite that was injected, but a toxin.

The Board then took the blood within the first three days of sickness from this second patient who had been given his disease from the blood of the first patient, and injected it into a third patient. This third patient developed the disease at the proper time. This experiment demonstrated that the virus so conveyed was capable of multiplying; that it was a living germ and not merely a toxin or chemical body which transmitted the disease.

The Board then took the blood of a patient collected in the first three days of his sickness, and passed it through a Pasteur filter so fine that it would stop any particle large enough to be seen with a microscope of the highest power. This blood when injected into a non-immune still gave yellow fever. This demonstrated that the parasite was sub-microscopic; that is, too small to be seen by a microscope of even the highest power.

They then took the blood of a yellow-fever patient within the first three days of his disease, heated it to 55° C., and injected it into a non-immune. The non-immune did not develop yellow fever. This was repeated three times. This experiment proved that the living parasite in the blood of the yellow-fever patient was killed by being raised to a temperature of 55° C.