﻿102 ASHBURN AND CRAIG. 



only having sent about 20 cases to the post hospital suffering from the 

 disease; three days before leaving it sent 5 more, but no cases developed 

 upon the voyage to Le}d;e, nor -have any cases appeared in this battalion 

 since arriving in Leyte. It seems to us that the almost instant disap- 

 pearance of dengue from these battalions upon their removal from Port 

 McKinley and their voyage by sea to Leyte is almost positive proof of the 

 relation of the mosquito to the transmission of the disease. It is obvious 

 that no mosquitoes were present upon the boat, and that, as probably no 

 cases were infected previously to embarking, the mosquitoes in Leyte did 

 not become infected, and therefore dengue did not continue in these 

 troops. 



Another fact of importance in considering the transmission of this 

 disease is the manner in which it spread from barrack to barrack. If 

 the disease were purely contagious we would expect contiguous barracks 

 to become infected in order. As a matter of fact, as shown by the map, 

 in which the barracks are numbered in the order in which they became 

 infected, contiguous barracks did not always become infected in the 

 order one would suppose; thus, of two barracks standing side by side, 

 one might be infected two or three weeks before the other, whereas 

 another several hundred yards distant from the first might be the 

 second one to become infected. A careful study of the map will show 

 that this is true in a great many instances, and it can be explained, 

 we think, by the erratic flight of an infecte.d insect, such as the mosquito. 



Lack of contagion is strongly suggested b} r the fact that although over 

 -±00 cases of dengue were treated in the general medical wards of the 

 post hospital, and although no special means were employed to prevent 

 contagion, no cases develojied in the wards except in three attendants 

 who were on night duty. 



In our own camp, where the patients under our observation were 

 treated, we have bad 128 cases. Here no person developed the disease, 

 except after inoculation and in consequence thereof, though attendants 

 and patients mingled freely, and we made every effort, as will be seen 

 in the detailed report of cases, to convey the disease by fomites, or air. 

 We had dengue patients and well men sleep together, eat together and 

 wear one another's clothing ; both sick and well meanwhile abstained from 

 bathing, and used a common close-stool kept in the tent with them. All 

 the sick recovered and none of the well men developed the disease through- 

 out the experiments, unless they were inoculated later. 



We therefore feel justified in stating that dengue is not contagious, 

 and think that the history and epidemiology, taken in connection with 

 C4raham'"s work and what we later detail, justifjr the correlative state- 

 ment that the disease is mosquito-borne. 



