Insects and Diseases / A Popular Account of the Way in Which Insects may Spread or Cause some of our Common Diseases

by Rennie Wilbur Doane

"I cannot pass on, however, to what I have to say in connection with this work without a word of admiration for the insight, the energy, the skill, the courage, and withal the modesty and simplicity of the leader of that remarkable band of workers. If any man deserved a monument to his memory, it was Reed. If any band of men deserve recognition at the hands of their countrymen, it is Reed's colleagues."

Their first work was to determine whether any of the germs that had been claimed to be the cause of yellow fever were really responsible for the disease. Bacillus icteroides that for some time and by some investigators had been named as the offender was particularly investigated, but was proved to be a secondary invader only.

Dr. Charles Finlay of Havana had been claiming for some years that the yellow fever was transmitted by means of the mosquito and possibly by other insects also. He even claimed to have proved this theory experimentally. We know now, however, that there must have been errors in his experiments and that his patients became infected from sources other than those he was dealing with.

The Yellow Fever Commission decided to put this theory to the test and secured a number of volunteers for the experiments. The first thing was to let an infected mosquito bite some non-immune person. How this was done and the results, may be told in Dr. Carroll's own words.

EXPERIMENTS

"Two separate lines of work now presented: one, the study of the bacterial flora of the intestine and anaërobic cultures from the blood and various organs; the other, the theory of the transmission of the disease by the mosquito, which had been advanced by Dr. Carlos Finlay in 1881. After due consideration it was decided to investigate the latter first. Then arose the question of the tremendous responsibility involved in the use of human beings for experimental purposes. It was concluded that the results themselves, if positive, would be sufficient justification of the undertaking. It was suggested that we subject ourselves to the same risk and this suggestion was accepted by Dr. Reed and Dr. Lazear. It became necessary for Dr. Reed to return to the United States and the work was begun by Dr. Lazear, who applied infected mosquitoes to a number of persons, himself included, without result. On the afternoon of July 27, 1900, I submitted myself to the bite of an infected mosquito applied by Dr. Lazear. The insect had been reared and hatched in the laboratory, had been caused to feed upon four cases of yellow fever, two of them severe, and two mild. The first patient, a severe case, was bitten twelve days before; the second, third and fourth patients had been bitten six, four and two days previously, and were in character mild, severe and mild respectively. In writing to Dr. Reed that night of the incident, I remarked jokingly that if there was anything in the mosquito theory, I should have a good dose. And so it happened. After having slight premonitory symptoms for two days, I was taken sick on August 31, and on September 1, I was carried to the yellow fever camp. My life was in the balance for three days, and my chart shows that on the fifth, sixth and seventh days my urine contained eighth-tenths and nine-tenths of moist albumin. On the day I was taken sick, August 31, 1900, Dr. Lazear applied the same mosquito, with three others, to another individual who suffered a comparatively mild attack and was well before I had left my bed. It so happened that I was the first person in whom the mosquito was proved to convey the disease.

"On the eighteenth of September, five days after I was permitted to leave my bed, Dr. Lazear was stricken, and died in convulsions just one week later, after several days of delirium with black vomit. Such is yellow fever.

"He was bitten by a stray mosquito while applying the other insects to a patient in one of the city hospitals. He did not recognize it as a Stegomyia, and thought it was a Culex. It was permitted to take its fill and he attached no importance to the bite until after he was taken sick, when he related the incident to me. I shall never forget the expression of alarm in his eyes when I last saw him alive in the third or fourth day of his illness. The spasmodic contractions of his diaphragm indicated that black vomit was impending, and he fully appreciated their significance. The dreaded vomit soon appeared. I was too weak to see him again in that condition, and there was nothing that I could do to help him.

"Dr. Lazear left a wife and two young children, one of whom he had never seen."