Reports and papers on epidemic poliomyelitis.

Date:: 1912

Credit: Reports and papers on epidemic poliomyelitis. Source: Wellcome Collection.

174/180 page 150

$In the above figures the so-called abortive cases are included. When these are left out the table becomes as follows for the houses in which at least two cases occurred :— No. of cases in each house ... ... 2 3 4 5 No. of houses ... ... ... ... 76 15 4 2 In the New York epidemic the cases studied were distributed as follows :— No. of cases in each house ... ... ... 1 2 3 No. of houses ... ... ... ... ... 700 18 5 The Committee who undertook the investigation of the New York epidemic make the following statement :— “ A study of the various epidemics leads to the conclusion that there is considerable variability both in the infectivity and the virulence of the causative agent. We have already noted the large proportion of multiple infections in the Swedish epidemic as com- pared to our own outbreak. So also in the small epidemic in St. Mary’s, Canada, in 1908, out of a total of 17 cases, three instances were observed of two cases in one family.” . . . “ The degree of infectivity does not necessarily correspond to the degree of virulence. The virulence of the infection can be measured not only by the mortality of the disease, but also in many instances by the proportion of adults affected and by the period of incubation.” In addition to instances in which two or more cases have been observed in the same family or the same house, instances have frequently been reported, in different epidemics, in which cases among acquaintances or neighbours were noted. Infected houses.—Cases are quoted by Wickman where the disease appeared successively for two or three years in the same house. He also records that persons, coming into a house previously invaded, themselves contracted the disease. School epidemics.—The observations of Wickman led him to the conclusion that schools may play a part in the propagation of the disease. At Trastena, where 49 cases occurred, Wickman traced the cause of contagion to children who attended a school in the neighbourhood. Of those who took ill, four children belonged to the school-teacher; 25 to families of which the first infected child attended the same school ; 12 to families who had healthy children attending school (the infected children being kept at home) ; lastly, four persons from families that had only indirect communication with the supposed seat of infection. This leaves a residue of only four cases who had apparently no ascertained connection with the school. Of the 49 cases, 23 were of the abortive type and 26 suffered from paralysis. Eleven of the paralytic cases died. There were 102 houses in the village of Trastena, 19 of which were invaded. The numbers affected in each house were as follows :— No. of cases in each house ... 1 2 3 4 5 No. of houses ... ... ... 6 3 5 3 2 Netter came to a similar conclusion in connection with an outbreak of poliomyelitis at Creteil. Seven children \>ere attacked$

Reports and papers on epidemic poliomyelitis.

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