February, '13] INFANTILE paralysis discussion 109 



Flexner, Howard and Clark in this country, and others abroad have 

 worked to some extent with insects of certain kinds to see whether 

 these could retain the virus of poliomyelitis in a virulent condition 

 in their bodies for any length of time. This has been done either 

 by allowing the insects to feed on bits of infected spinal cord, or by 

 allowing them to suck the blood of infected monkeys. After varjdng 

 periods the insects were then ground up in a mortar and injected 

 intracerebrally into monkeys. Positive results have been obtained in 

 the case of house flies, bedbugs, and possibly with fleas, but only 

 negative ones with several species of mosquitoes and lice. In all 

 these cases, it must be remembered that the pulverized insects were 

 injected into the brains of the monkeys, so that these results do not 

 have a very direct bearing on the epidemiology of the disease. 



The fact that Stomoxys does not bite children so very frequently 

 suggests that perhaps poliomyelitis may possibly be regularlj^ spread 

 from some domestic animal which acts as a reservoir for the virus, 

 and it has long been suspected that this disease in man may bear a 

 relation to some paralytic disease of animals. On the other hand, the 

 numerous mild cases which are usually regarded as abortive poliomye- 

 litis may serve as reservoirs as well as the paralytic cases, and then 

 the frequency with which Stomoxys bites might account for the inci- 

 dence of the disease without any connections with animals. These 

 are matters w^hich w411 require much further study. 



President W. D. 'Hunter: This paper is open for discussion. 



Mr. C. L. Marlatt: I would like to ask a question, and that is, 

 do I understand, from the diagram exhibited showing occurrence of 

 the disease in the winter months (December, January, February, etc.), 

 that the disease originated in these months, or are these cases carried 

 over from the summer? 



Mr. C. T. Brues: We have no evidence except that the winter 

 development of the disease is rather more than might be expected 

 from the rarity of the fly in the winter. 



Mr. C. F. Hodge: We have been working on the habits of this 

 insect and are surprised to find them in the winter in the stable biting 

 animals. 



Mr. Brain: I think Prof. Brues and his colleagues have made a 

 very important advance in the subject of medical entomology by the 

 discovery of the connection between Stovioxys caldtrans and Poliomye- 

 litis, but I feel that a further step is necessary, and that is to ascertain 

 how many bites of this fly are necessary for the transmission. In 

 these experiments some 300 flies were used, but it is not known how 

 many fed on any particular day, nor how many fed before infection. 



