FAMILY ERROXACEAE 



1257 



Genus II. Legio gen. nov. 



Viruses of the Poliomj-elitis Group, often recoverable from feces of infected hosts 

 probably because of involvement of some part of the alimentary tract ; usually there is 

 also obvious involvement of some part of the nervous system. Generic name from 

 Latin legio, an army or legion. 



The type species is Legio dehilitans spec. nov. 



Key to the species of genus Legio. 

 I. Affecting man (see also IV below) . 



1. Legio dehilitans. 



2. Legio crebea. 



3. Legio simvlans. 

 II. Latent in, or affecting, mouse. 



4. Legio initris. 



III. Affecting birds. 



5. Legio gallinae. 



IV. Affecting swine and swineherds. 



6. Legio suariorian. 



1. Legio dehilitans spec. nov. From 

 Latin debilitare, to weaken or maim. 



Common names: Poliomyelitis virus, 

 virus of infantile paralysis. 



Hosts : HOMINIDAE — Homo sapiens 

 L., man. Experimentallj-, Cercopiihecus 

 aethiops sabaeus, green African monkey; 

 Macaca mordax; M. nndatla, the rhesus 

 monkej'; M. irus, the cynomolgus mon- 

 key; mona monkey; for some isolates, 

 Sigmodon hispidus Say and Ord, cotton 

 rat ; mouse ; guinea pig; white rat. 



Insusceptible species : Sheep ("refrac- 

 tory"biit forms neutralizing antibodies), 

 chicken. 



Geographical distribution; Almost 

 world-wide. 



Induced disease : In man, probably sub- 

 clinical in most cases, in view of the 

 presence of specific antibodies in sera 

 from the great majority of adults in all 

 parts of the world; virus probably infects 

 some part of the alimentary tract, being 

 found in stools of most clinical cases, of 

 most apparently healthy contacts, and 

 even of some individuals who have recov- 

 ered from abortive attacks (in one case 

 123 days after attack); clinical disease, 

 largely in children, is characterized by 

 invasion of central nervous system, with 

 effects ranging from sore throat, fever. 



vomiting, and headache to sudden and 

 severe paralysis; the muscles most often 

 involved are those of the legs, but there 

 may be paralysis of abdominal or inter- 

 costal muscles. Virus not in urine or 

 saliva, rarely in nasal washings; more of- 

 ten in stools of young than of old patients ; 

 in walls of pharynx, ileum, descending 

 colon. Virus has been recovered from 

 sewage. Incidence and fatality affected 

 by racial characteristics, the first lower 

 and the second higher in negroes than in 

 whites in the L'nited States. In monkey, 

 similar disease, no virus in blood, relapse 

 with reappearance of virus reported; in 

 isolated intestinal loops, infection does 

 not occur through normal mucosa in 

 absence of intestinal contents; disease 

 more severe in summer than in autumn, 

 in autumn than in winter; more severe in 

 older than in younger monkeys; no im- 

 munit}' follows inoculation unless obvious 

 disease occurs. 



Transmission : Transmission in milk 

 has been suspected and at times con- 

 firmed. Virus has been recovered from 

 mi.xed samples of flies in an epidemic 

 area. No definite arthropod vector has 

 been incriminated. Experimentally, in 

 Cercopithecns aethiops sabaeus, the green 



