We entered the outbreak with a notion that we knew the cause of the disease, and were quite sure we knew how it was transmitted from person to person. Perhaps, if we have learned anything, it is that we are not quite sure what we know about the disease.MILTON J. ROSENAU, M.D.
in JAMA, Aug 2, 1919
A little over a century ago, Doctor Rosenau published his findings in the Journal A.M.A. in an article titled EXPERIMENTS TO DETERMINE MODE OF SPREAD OF INFLUENZA; in particular the devastating “Spanish Flu”.
In the Gallop Island Experiments, 100 volunteers, without a history of recent influenza, were exposed to infections by a number of plausible vectors.
In early preliminary trial, a few volunteers were, for example, directly exposed to a culture of Pfeiffer’s bacillus, at the time thought to cause influenza. But all preliminary trials failed to produce symptoms of influenza.
In the experiment, a group of 19 was exposed to Pfeiffer’s bacillus, sprayed into their nostrils, throat and eyes while they were inhaling. None took sick.
Saline lavages and mucus were extracted from symptomatic influenza patients and transferred directly to 10 volunteers by nostrils, throat and eye sprays. The same concoction, further filtered was “instilled” into further volunteers; again failing to produce flu-like symptoms.
To preclude the saline solution deactivating the suspected pathogen, mucosal samples were directly transferred from symptomatic patients to 19 volunteers; accepting multiple “shots”. No volunteers fell ill within the week of post-exposure observation.
Whole blood from symptomatic patients was injected into a further 10 volunteers; without producing flu symptoms in any of the volunteers.
Mucus from influenza patients were filtered and injected subcutaneously into a further 10 volunteers. None of the volunteers became ill.
Attempting to mimic what was believed to be the most-likely means of infection, 10 volunteers were introduced into a ward of 30 influenza sufferers with active symptoms. Each volunteer made physical contact by shaking hands and engaged in conversation with a patient for 5 minutes, then deliberately breathing in the patient’s expelled air. This was repeated 5 times, ending with the patient coughing directly into the volunteer’s face.
None of the volunteers fell ill within the 7 days of subsequent observation.
Having run out of experimental material, researchers went on vacation. When they returned, there was a shortage of donors; i.e. infected patients with influenza.
Volunteers that they could muster who did fall ill were found to have a bacterial streptococci infection. “Strep. throat”. One of the medical staff developed a case of clinical influenza some 36 hours after collecting samples.
In full, Rosenau concluded:
I think we must be very careful not to draw any positive conclusions from negative results of this kind. Many factors must be considered. Our volunteers may not have been susceptible. They may have been immune. They had been exposed as all the rest of the people had been exposed to the disease, although they gave no clinical history of an attack.
Dr. McCoy, who with Dr. Richey, did a similar series of experiments on Goat Island, San Francisco, used volunteers who, so far as known, had not been exposed to the outbreak at all, also had negative results, that is, they were unable to reproduce the disease. Perhaps there are factors, or a factor, in the transmission of influenza that we do not know.
As a matter of fact, we entered the outbreak with a notion that we knew the cause of the disease, and were quite sure we knew how it was transmitted from person to person. Perhaps, if we have learned anything, it is that we are not quite sure what we know about the disease.