SECOND ATTACKS OF EXPERIMENTAL POLIOMYELITIS IN MACACUS RHESUS MONKEYS

Abstract

In previous experiments, monkeys (Macacus rhesus) which had survived attacks of experimental poliomyelitis were reinoculated with homologous and heterologous strains of virus.¹ Nine of these strains were evaluated.² Recently Flexner isolated a strain of virus from the spinal cord of a patient who died during the Philadelphia epidemic of 1932. He demonstrated that this strain when introduced intranasally into monkeys was extremely efficient in producing the disease. He also showed that it caused second attacks in monkeys when the intranasal portal of entry was used.³ The object of the experiments described in the present paper was to determine whether monkeys (Macacus rhesus) which had survived previous attacks of poliomyelitis after having been intracerebrally inoculated with heterologous strains of virus would have second attacks when subsequently inoculated intracerebrally with this recently isolated strain. METHODS AND MATERIALS A subpassage strain of the Philadelphia strain of virus was obtained from