CHAPTER XL VI 



ACUTE ANTEEIOE POLIOMYELITIS 

 LETHARGIC ENCEPHALITIS 



THE disease known as acute anterior poliomyelitis has long been 

 recognized as an acute infectious condition, both because of the char- 

 acteristics of its clinical manifestations and of its epidemic occur- 

 rence. For these reasons it was classified with acute infectious dis- 

 eases by Marie and by Striimpell long before any experimental 

 evidence of infection was obtained. 



Its contagiousness, while not a proven fact, seemed very likely 

 from the evidence of its mode of spreading and has been removed 

 from the sphere of mere conjecture by the careful study of a Swedish 

 epidemic, comprising one thousand cases, made by Wickman. 1 



While acute anterior poliomyelitis is almost exclusively a disease 

 of childhood, it is assumed by clinicians that it is etiologically 

 closely related to, possibly identical with, certain diseases of the 

 adult, characterized by bulbar paralysis and acute encephalitis. Into 

 this category, also, some observers place the condition known as 

 ' ' Landry 's paralysis. ' ' The basis for the identification of these con- 

 ditions with poliomyelitis lies chiefly in the similarity of the pathol- 

 ogical lesions and upon the fact that the last-named diseases occur 

 most often during the course of poliomyelitis epidemics. The writer 

 some years ago obtained a typical poliomyelitis infection in a monkey 

 with material from a definite case of Landry 's paralysis in a young 

 woman. 



The most thorough recent clinical study of acute poliomyelitis of 

 which we know is the one by Peabody, Draper and Dochez. 2 The 

 incubation period of the disease varies, but appears to be about 10 

 days. Prodromal symptoms, if they appear at all, come on just 

 before the onset of the disease. They may be very mild, consisting 



1 Wiclcman, quoted from Landsteiner and Popper, Zeit. f. Immunitatsforch., 

 ii, 1909. 



2 Peabody, Draper and Docliez, Monog. Eock Inst., 4, Jan., 1912. 



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