An Electron Microscope Analysis of Nerves Infected

The demonstration with the electron microscope that the nerve contains a fibrous component, probably axonic, the so called neurotubules (De Robertis and Schmitt (1)) has led to the supposition that these structures might be involved in the transfer of virus particles through the axon. This hypothesis was first tested with the poliomyelitis virus (2). In experimentally infected monkeys, neurotubules were found which contained dense particles of the order of size generally assumed for poliomyelitis virus. The rate of progression of the particles inside the nerves is also within the range determined by indirect studies of the poliomyelitis virus transfer (Bodian and Howe (3)). I t was concluded that although the identification of these dense particles could not be definitely stated they appeared to be related to the advancing virus infection (4). In the present investigation the pantropic B virus was used. This virus follows a regular and constant pattern of progression when injected into the gastrocnemius muscle of the rabbit. As Sabin (5) has shown, up to 48 hours after injection the virus grows in the muscle but is not detectable in the nerve or in the cord. Between 72 and 96 hours the virus is detectable in the sciatic nerve, but in small concentration. Later, multiplication of the virus particles occurs in the sciatic and cord and reaches a maximum at the onset of paralysis on the 6th day. At this moment the virus can be detected also in the left sciatic as a result of centrifugal spread from the spinal cord (Sabin). The results which will be described here show a clear correlation with the abovementioned findings of Sabin inasmuch as dense particles can be found in the neurotubules of nerves known to contain virus and their concentration with time follows a pattern similar to the one demonstrated by the virus assay.