Recently, a strong correlation between high concentration of tumor necrosis factor (TNFalpha) in blood and severity of dengue hemorrhagic fever/dengue shock syndrome has been reported from Asia and the Pacific. We wished to determine if a similar relationship could be found in dengue patients in the Americas where adult patients with severe syndromes have been observed more frequently than in Asia where severe cases have been observed mostly among children. The concentrations of interleukin-1 (IL-1beta) in hospistalized adult groups were significantly lower than that in outpatient adults. In contrast, the levels of interleukin 6 (IL-6) were significantly higher in hospistalized adults and children than in the corresponding outpatients. Levels of TNFalpha were higher in hospistalized children than in outpatient children or hospistalized adults. There was no significant difference in the levels of these three cytokines among hospitalized patients with or without hemorrhagic manifestations. Thus, an elevated IL-6 level was positively associated with severity of dengue infection in both children and adults, but IL-1beta level was negatively associated with severity in adults.
An outbreak of dengue 4 occurred in the Yucatán, México in 1984. During the course of the outbreak, 538 of 5486 reported cases of dengue-like illness were studied; 200 were confirmed as dengue serologically and/or virologically. Dengue 4 virus was isolated from 34 patients and dengue 1 from one. Severe haemorrhagic symptoms were observed in 9 laboratory confirmed patients, including four deaths. Thus, the outbreak in Yucatán is the second dengue epidemic in the Americas after the Cuban epidemic in 1981 in which a number of patients suffered from haemorrhagic complications. It was notable that 5 of 9 hospitalized, severe cases were young adults and that only one met the WHO criteria of DHF, in contrast to primary pediatric nature of DHF in Southeast Asia. In this paper we describe clinical, serologic, and virologic studies conducted during the outbreak.
Un brote de dengue 4 ocurrió en Yucatán, México en 1984. Durante el curso del brote, 538 de 5486 casos reportados como dengue clínico fueron estudiados; 200 fueron confirmados como dengue, por estudios serológicos y/o virológicos. El dengue tipo 4 fue aislado de 34 pacientes y dengue 1 de un paciente. Síntomas hemorrágicos severos fueron observados en 9 pacientes confirmados por pruebas de laboratorio, de los cuales 4 fallecieron. Así, el brote en Yucatán es la segunda epidemia de dengue en las Américas después de la epidemia en Cuba en 1981 por el número de pacientes que sufrieron de complicaciones hemorrágicas. Fué notable que 5 de 9 casos hospitalizados, fueron adultos jóvenes y que únicamete un paciente reunió los criterios de la Organización Mundial de la Salud para la Fiebre Hemorrágica por Dengue (FHD), en contraste con los casos pediátricos de FHD del Sureste de Asia. En este artículo describimos los estudios clínicos, serológicos y virológicos realizados durante el brote.