XII, B. 2 Proceedings of the Manila Medical Society 109 



PUBLIC HEALTH ASPECTS OF POLIOMYELITIS 



By Hugh de Valin 



[Abstracted.] 



The increase of poliomyelitis and the numerous epidemiological 

 problems which it presents to be solved make it of special in- 

 terest and concern to health officials. Through experimental 

 studies on the monkey the virus has been demonstrated in the 

 secretions from the mucous membrane of the nasopharynx and 

 intestines of human convalescents and in the secretions from 

 the nasopharynx of healthy persons v^^ho have been in more or 

 less intimate contact with poliomyelitis patients. This latter 

 class of individuals constitutes the so-called "healthy carriers" 

 of the disease. 



The virulence of the virus, inoculated into monkeys, seems 

 not to be correlated with the severity of the degree of illness 

 of the patient as evidenced by clinical symptoms. The virus 

 may be found on the mucous membrane of the nasopharynx up 

 to six months, though it disappears from the central nervous 

 system within a few days to three weeks after the appearance 

 of the paralysis. In man the few examinations recorded have 

 given positive findings several weeks after recovery, and in one 

 case the virus persisted for five months (Flexner). 



The virus presents a marked degree of resistance to drying, 

 to climatic temperature change, and to antiseptic solutions in a 

 strength which may be fatal to ordinary bacteria. Transmission 

 seems possible by dust of rooms of poliomyelitis patients (as 

 the virus has been recovered from this source), as well as by 

 sneezing, kissing, from hands, or from contaminated articles. 



Insects such as bedbugs, mosquitoes, and lice have not been 

 shown experimentally to convey the disease; the stable fly 

 (Stomoxys calcitrant) has been considered as a possible carrier 

 from monkey to monkey, but later investigations have failed to 

 confirm this. The virus does not seem to be found in the blood 

 of man, as is the case for monkeys, an observation which dimin- 

 ishes the probability of transmission by blood-sucking insects. 

 The fly, cockroach, and other insects may play important roles 

 as mechanical carriers of the infection. Richardson suggests 

 that the rat may be the chief agent for the spread of this disease 

 as for plague; he gives instances of the occurrence of polio- 

 myelitis where association has been demonstrated between human 

 cases and apparent rat foci. Domestic animals do not seem to 

 be carriers of the virus except possibly in a mechanical way. 



