Fig. 138.—Dengue. Analysis of Symptoms, from 100 cases occurring in epidemic at St. Thomas, V. I. (After Lane, from U. S. Naval Medical Bulletin.)
The respiratory involvement of influenza and the eruption and comparatively slow pulse of dengue are the principal points of difference. It must be remembered that affections in the tropics, diagnosed as influenza, have shown but slight respiratory symptoms, the cases being more of a nervous or intestinal type. The eruption of dengue may fail to appear or be missed in the study of the case. The blood findings should aid in differentiation from influenza as is also true of yellow fever, a disease which likewise has blood findings of practically a normal character. Other than the blood picture we have in yellow fever (1) albuminuria, coming on about the second day, and (2) jaundice appearing about the third day. In dengue the eruption appears from the third to the fifth day. Albuminuria is absent in dengue.
Dengue may be mistaken for measles, but the early coryza, Koplik spots and marked rash, first appearing about the face, should differentiate.
In scarlet fever the rapid pulse, angina and leucocytosis should be sufficiently differentiating.
Confusion with articular rheumatism may arise when the pain about wrists, knees and ankles has been mistaken for true joint involvement.
The headache and backache of smallpox may be confusing until the eruption about the forehead appears. The leucopenia of dengue is the main differential point in these first three days of doubt.
Prophylaxis and Treatment
Prophylaxis.—This would seem to rest entirely upon the question of destruction of mosquitoes and prevention of the mosquito from biting a patient. In dengue the virus is apparently in the blood for four or five days so that screening of patients is necessitated for a longer period than for yellow fever or phlebotomus fever.
Treatment.—The malaise and depression are generally so great that the patient keeps his bed voluntarily. A light diet is indicated although the anorexia is so marked that it is difficult to persuade a patient to take food.