Comparative Effectiveness of Various Chemical Sprays in Protecting Monkeys against Nasally Instilled Poliomyelitis Virus

Abstract

We reported 1 the protective action of sodium alum and tannic acid instillations against nasally instilled poliomyelitis virus in Rhesus monkeys. It was pointed out that the action of these chemicals was dependent on their concentration and was exerted on the nasal mu-cosa of the host rather than on the virus, although it appeared from one experiment that the potency of the test dose of virus influenced the results. Upon resuming this work at a later date we were unable to repeat our original results with sodium alum. Investigation of this failure disclosed the participation of the following factors: (1) the sodium alum which we used in the original experiments was assumed to have 24 molecules of water of hydration (as indicated by the manufacturers'label) while actually it possessed only 2 molecules and contained some insoluble A1₂O₃; (2) the sodium alum used in subsequent experiments really had approximately 24 molecules of water of hydration, had no A1₂O₃ and gave a clear solution, so that the actual amount of Na₂SO_4. Al₂ (SO₄)₃ in a 4% solution of this preparation was in the ineffective range; (3) that the virus used in the subsequent experiments had become for some unknown reason considerably more potent; while originally only about 80% of control monkeys developed poliomyelitis, all untreated animals now succumbed even when the dose of virus was reduced.

In an attempt to elucidate further the mechanism of the protective action of these chemicals as well as to find the most effective substance, experiments were performed with a number of astringents which are used in human beings for one purpose or another. Rather than reduce the test dose of virus to a point where only a majority of .untreated monkeys would develop poliomyelitis and have a larger number of agents exhibit protective properties, the more highly infective amount of virus was used (regularly paralyzing all untreated monkeys) to discover whether under these conditions any of the substances would still be effective. It was furthermore realized that a reliable comparison of the effectiveness of various chemicals can be made only when all the substances to be compared are used in a single experiment under identical conditions of treatment and infection—for even with 100% infectivity the potency of various virus preparations can vary in different experiments.

The astringent solutions were sprayed into the nostrils by hand with a DeVilbiss atomizer, delivering approximately 1.5 cc. of the solution in each side of the nose by means of 10 to 15 bulb compressions. The monkeys were thus treated once a day for 7 days, and 2 days after the last spraying poliomyelitis virus was instilled into the nose. The monkeys were then observed for a month, and those which survived and failed to develop paralysis were, without any additional chemical treatment, again instilled with virus, the processes being repeated until practically all monkeys became paralyzed, thus indicating the duration of chemical protection. The virus consisted of pooled glycerolated bits of spinal cords from 4 to 6 paralyzed monkeys, ground up to a 5% suspension in physiological saline solution and centrifuged only enough to eliminate the alundum and large tissue particles. One cc. of this suspension was dropped into each nostril in the morning and then again in the afternoon of the same day.