Biological Changes in Theiler's Virus of Spontaneous Mouse Encephalomyelitis

Abstract

In 2 of 4 expts., in which Theiler''s virus of mouse encephalomyelitis was transmitted to cotton rats with subsequent serial subpassage in the latter animals, the virus became fixed in the new host and acquired new biol. properties reflected by a marked increase in peripheral invasiveness for albino mice and cotton rats, and ability to induce various types of central nervous system involvement in guinea pigs and in rhesus monkeys. Evidence is adduced to show that the cotton rat variant was serologically identical with the parent virus.