Studies on entry and egress of poliomyelitic infection. V. Entry after simple feeding: with notes on viremia.

Poliomyelitis virus, when ingested by cynomolgus monkeys in their regular food, infected peripheral ganglia (nodose) as early as the 3rd day, as shown by recovery of the virus. Conditions on the 2nd and 4th days were not investigated, but on the 5th and 6th days, virus was recovered from the Gasserian and nodose ganglia, and from the superior cervical sympathetic and celiac ganglia. The findings indicate that the method of oropharyngeal swabbing used in a study already reported and the method of simple feeding used in the present study produce comparable results. Viremia, noted in the present study, was contemporaneous with virus recoveries from the ganglia. Reasons are presented why the peripheral ganglia are the most probable source of viremia since these are the only known site of early lesions (which are typical and appear as early as the 2nd day after oral infection) and no lesions are known to occur in extraneural tissues. Invasion of the CNS occurred in 3 animals out of 11; one on the 5th and 2 on the 6th day. Whether this was due to viremia or to centripetal extension along axonal channels is not clear.