Studies on Chemical Prophylaxis of Experimental Poliomyelitis

Olfaction and Olfactory Epithelium in Mice Treated With Zinc Gluconate

“…The first fact to note in the polio literature is that the technique of applying zinc sulfate differed from that used in conventional nasal sprays such as Zicam. The early failures of potentially toxic nasal sprays in protecting against infection were initially attributed to the failure of the spray to make contact with the olfactory epithelium 8,9,11,13 . For example, the failure of a picric acid and alum spray to protect against polio in more than 5,000 persons in Alabama, Tennessee, and Mississippi was discounted because it was unlikely that the spray made contact with the nasal epithelium 10 .…”

“…If Jafek et al 5 and Alexander and Davidson 4 are correct, their hypothesis should be reproducible in an animal model. Second, an examination of the zinc sulfate polio literature reveals no empirically documented cases of permanent anosmia, and production of even a transient hyposmia or anosmia required application of the salt by a trained person using long tubular atomizer inserted beyond the middle turbinate 6–10 . The difference between the formulary and method of administration used in animal studies and to control polio versus that used in current cold medications raises the question whether this difference in degree might not really be a difference in kind.…”

Re: Alexander TH, Davidson TM. Intranasal zinc and anosmia: the zinc‐induced anosmia syndrome. Laryngoscope 2006;116:217–220.

“…Seidman appears to be unaware of the extensive literature and acceptance by the scientific community of the loss of smell resulting from intranasal zinc ions. Zinc olfactory toxicity was extensively reported by Schultz in the 1930s and standardized for rodent work in 1971 by Alberts 2–4 . Slotnick tabulated almost 90 publications regarding zinc olfactory toxicity in a variety of animal experiments, including such diverse species as turtles, goats, hamsters, catfish, monkeys, and humans (“Table.…”

“…I have several immediate concerns regarding Dr. Seidman's Letter to the Editor: 1) Dr. Seidman acknowledges that “it has been well established that “zinc sulfate [meaning zinc ions, my addition of Schultz' observations 3 ] … can disrupt the olfactory epithelium.” He claims, however, that this is “brief” and “fails to cause permanent anosmia in animal studies.”Harding et al studied the long‐term toxicity of zinc ions on the olf/ctory epithelium in 1978 and reported 80% anosmia in mice treated with 0.17 mol/L zinc sulfate at 6 weeks, 50% anosmia at 4 months, and persistent losses at 1 year, the limit of the study. They concluded “more than 1 year after ZnSO4 treatment, much less than 10% of the epithelium–bulb complex has recovered normal structure and function.” 8 Schultz specifically warned, after his extensive studies of the zinc ion in the 1930s, “ against the further use of zinc sulfate in man until more is known about … the risk of inducing permanent anosmia in man ” [my emphasis] 9 …”

Chemotherapy of Virus and Rickettsial Infections

“…In earlier work, the chemoprophylaxis of poliomyelitis in the rhesus monkey was accomplished by chemical blockade of the olfactory tissues us ing alum, zinc sulfate, tannic acid, picric acid, pituitrin S, or other materials (176,177,178). These substances produced a coagulation necrosis of the olfactory epithelium followed by sloughing and the formation of a new epi thelium which appeared to remain resistant until the time of regeneration of some of the olfactory neurons.…”