182 OTHER SPOROZOA 



Dengue and Phlebotomus Fever 



These two diseases are wide-spread in tropical and subtropical 

 countries, and are frequently confused. They have commonly 

 been associated with yellow fever, none of the parasites causing 

 them having been discovered until Noguchi discovered a* Lep- 

 tospira as the causative organism of yellow fever in 1918. It is 

 possible that the other two diseases will also be shown to be 

 caused by species of Leptospira. Dengue is a much milder disease 

 than yellow fever and is seldom fatal, though its after-effects 

 linger for many months. Phlebotomus or three-days' fever is a 

 still milder disease and, as its name implies, of short duration. 

 Like dengue it has lingering after-effects but they are not so severe 

 or so persistent as in the former disease. 



Both diseases are caused by blood parasites, so far undiscovered, 

 which are transmitted by dipterous insects in which they ap- 

 parently undergo part of their life cycle. The diseases each begin 

 with a sudden high fever and headache, and pass through es- 

 sentially similar stages, intense rheumatism-like aches being very 

 characteristic of all. Each disease confers immunity, often of 

 long duration in dengue and often transitory in phlebotomus 

 fever. It seems not improbable that the parasites of these dis- 

 eases and of yellow fever are closely allied. 



Dengue 



Dengue, seven-days' fever, or breakbone fever, is a disease of 

 tropical and subtropical countries. It is very common in the 

 West Indies and great epidemics have swept through Panama, 

 the eastern Mediterranean and southern Asian countries, the 

 Philippine Islands and various South Sea Islands, An epidemic 

 has recently been reported from Argentina and Uruguay, the dis- 

 ease supposedly having been introduced from Spain. Dengue also 

 occurs in southern United States where it is probably often over- 

 looked, being diagnosed as something else. In some places, e.g., 

 southeastern Europe and India, there is some confusion between 

 dengue and phlebotomus fever. Both diseases vary somewhat 

 and mild types of the former and severe types of the latter may 

 easily be, and frequently are, confused. Dengue occurs in the 

 form of sudden and rapidly spreading epidemics which sweep 



