Dengue has certain characteristics in common with yellow fever. The late Henry R. Carter (1) often said that it was very difficult to differentiate between dengue and yellow fever during the first two or three days of the attack. Both show much the same type of inflammatory onset, with a congestion of the conjunctiva and other mucous membranes and general aches and pains. The pains in dengue are more intense, and there is a greater degree of restlessness than in yellow fever. In yellow fever there is a profound prostration almost from the onset of the disease, and the patient is disinclined to talk, which is not the case in dengue.
During recent years there have been no opportunities to compare the two diseases within the continental United States. The last appearance of yellow fever was in 1905, in New Orleans and in Pensacola.