Luther Dong

Inactivation of poliomyelitis virus in relation to gastric and intestinal digestion.

Summary At the pH levels prevailing in the stomach when only gaitric juice is present, and at the height of digestion of carbohydrate and mixed meals containing meat, poliomyelitis virus is rapidly inactivated. Pepsin contributes slightly to inactivation. Since the pH levels necessary for virus inactivation are present in the Stomach only part of the time, and since part of the gastric contents are evacuated before such level can be attained, acertain proportion of ingested virus has the opportunity to escape intactinto the duodenum, here and in the rest of the intestine the pH is too high to inactivate and trypsin has no inactivating effect. Virus entering the bowel therefore must be presumed to remain active, thus providing conditions suitable for secondary intestinal entry of infection, and also for concentration of virus in the contents of the large intestine.

Excretion of Poliomyelitis Virus.

Summary Poliomyelitis virus when applied to the central end of a divided branch of the trigeminal nerve in the cheek travels centripetally to the corresponding semilunar ganglion within three days. Centrifugal spredd to the nasopharyngeal surfaces, which are supplied by the trigeminal nerve, was demonstrated by detection of virus in the nasopharyngeal washings on the third and fourth days. Virus was also found in the stools on the fourth but not on the third day, suggesting that it had been swallowed. It is suspected that excretion, like invasion, of poliomyelitis virus occurs through axonal channels.