THE TOLL OF THE MOSQUITO 



1 1 



Dengue is believed to be transmitted by Culex fatigans, 

 although the causative factor is as yet unknown. Graham 1 

 described a protozoon which he believed caused the disease, but 

 Ashburn and Craig 2 assert that a filterable virus is responsible 

 for it. They placed the period of incubation at 3 days and 14 

 hours. 



Dengue somewhat resembles yellow fever in its rapid com- 

 municability, sometimes spreading with marvelous rapidity and 

 infecting virtually every person within its vicinity. Unlike 

 yellow fever, however, there is no definite immunity. 



The prevalence of dengue in the United States and territories 

 during the fiscal years 1918 and 1919 is reported by the U. S. 

 Public Health Service as follows: 



1918 



1919 



States and territories 



Cases 



Deaths 



Cases 



Deaths 



Texas 



Louisiana . 

 Colorado . . 

 California . 

 Florida . . . 

 Porto Rico 

 Hawaii . . . 



24 

 4 



I 



127 



71 



1 



12 

 345 



While cases of dengue in the United States are comparatively 

 few, as indicated by the above table, it is certain that in South 

 and Central America and other tropical and sub-tropical coun- 

 tries the morbidity from this disease reaches a not inconsiderable 

 figure. 



FILARIASIS 



This disease consists of the infestation of the connective tissues, 

 lymphatics and body cavities of man with larvae or adults of 

 filaria, a long, slender threadworm with a curved tail. According 

 to Rosenau, 3 none of the young worms do any appreciable 

 injury to the blood, while of the adult worms only one, Filaria 



1 Journal of Tropical Medicine, vol. 6, 1903; quoted by Rosenau. 



2 Philippine Journal of Science, May 1, 1907; quoted by Rosenau. 



3 "Preventive Medicine and Hygiene," New York and London, 1918. 



