Infection of Monkeys With Poliomyelitis Virus by the Gastro-Intestinal Route.

Abstract

Aycock 1 , 2 has recently reported 3 outbreaks of poliomyelitis which he believes can be traced to contaminated milk. The observations recorded by Aycock are of particular interest in the face of essentially negative results which have been realized under experimental conditions. Leiner and v. Wiesner 3 succeeded in producing the disease in only 2 out of 5 monkeys fed with large quantities of the virus, after neutralizing the hydrochloric acid of the stomach with sodium bicarbonate and reducing the motility of the intestines with morphia. Following the same procedure, Amoss 4 obtained entirely negative results, even though the monkeys were fed a considerable quantity of the virus over a period of 42 days. The animals not only failed to develop the disease, but also failed to acquire an immunity as a result of the massive ingestion of virus material. Levaditi and Landsteiner 5 were unsuccessful in producing infections in monkeys fed with virus-contaminated milk. No immunity was noted on subsequent intracerebral inoculation.

Though the results reported appeared to indicate quite clearly that in monkeys, at least, infection by the gastro-intestinal tract is extremely difficult, if not practically impossible, nevertheless, the important observations made by Aycock seemed to justify a repetition of feeding experiments in monkeys.

We have accordingly endeavored to infect 2 normal monkeys with heavily contaminated milk. In order that natural conditions might be maintained, nothing was previously done to the monkeys except to subject them to a brief period of fasting. The animals then had placed before them approximately 150 cc. of milk containing about 7 gm. of a finely ground cord and medulla of a monkey having recently succumbed to the disease (P.M. No. 44). This the animals consumed entirely within 2 hours. Several hours later (in the evening) a similar quantity of virus in milk was placed before them, this time prepared from the cord and medulla of another monkey (P.M. No. 70) having succumbed to the disease.