Aedes Simpson was demonstrated to have been an important vector in this epidemic. Scattered among the necrotic cells are Councilman bodies, parenchymal cells that have undergone eosinophilic hyaline necrosis. The liver lobules are not collapsed. Pathologic changes in the kidneys are seen mainly in the tubules, with extensive damage to the epithelium and with lumina containing debris, casts, and basophilic concretions. Clinical Manifestations.
The epidemiological implications of this disease make a diagnosis of great importance, and it is essential to maintain a high index of suspicion with regard to undiagnosed fevers vernacular Oar The incubation period is from three to six days. The symptoms are feverish feeling, severe headache, backache, pain in the legs, and prostration. The face is flushed, and the eyes are injected; there is photophobia. There is no jaundice at the onset of illness Nausea and vomiting are the rules, as are epigastric distress and tenderness. Constipation is to be expected.
A progressive leukopenia, sometimes pronounced, has frequently been observed early in the disease. After a short remission, the period of intoxication begins about the fourth day. In this period, lassitude and depression may replace restlessness and agitation. Headache may diminish, and jaundice gradually develops. Various hemorrhagic manifestations are evident. The gums are swollen and bleed easily, either spontaneously or when pressed; the nose may bleed. There may be petechiae on the skin. Hemorrhages from the stomach, intestine, or uterus, or subcutaneously, may be massive. Vomiting may be frequent and distressing, and the vomitus in this stage usually contains altered blood, whence the name “el vomito negro” often applied to the disease in Latin America.
Aedes Simpson Death occurs most frequently from the sixth to the ninth day. Convalescence begins then and progresses rapidly to complete recovery with rapid disappearance of the albuminuria. Re-lapses do not occur, and there are no sequelae. Complications are rare. A feature of yellow fever is a great variation in the degree to which different organs are affected. With much renal involvement, there may be no cardiac symptoms, and vice versa. In mild and moderate cases there is little or no albuminuria, jaundice, or hemorrhage. Diagnosis. In mild cases, which have been confused with dengue and influenza, clinical diagnosis is notoriously inaccurate.
The necessary laboratory procedures are highly specialized. The isolation of the virus in mice, rhesus monkeys, or certain tissue cultures from the serum of the acutely ill patient or from serum or liver of a deceased patient affords convincing diagnosis. Specialized procedures are needed for the identification of the isolate. Serologic tests on paired acute-phase and convalescent serums. using techniques of complement-fixation, hemagglutination-inhibition, and ‘virus neutralization can also give a positive diagnosis. Although the tests must be done in a specialized laboratory.