During active infection, dengue virus stimulates immune system to react, producing release of cytokines with vasoactive and procoagulant properties, which are required for recovery of infection. The early phase of DHF is similar to that of the classical dengue fever and usually lasts about 2 to 5 days. Still, cold extremities, dyspnea, cyanosis are also related. Jaundice may occur. Diffuse capillary leakage leads to hemoconcentration, edema, hypoalbuminemia and pleural effusion.
Respiratory distress reflects pulmonary edema.
Cerebral hemorrhage is rare. Definitive diagnosis is established by isolating infectious virus from the patient's blood. Viruses are more easily demonstrated during the fifth day of illness. Specific serotypes can be determined by the indirect fluorescent antibody test with the use of type-specific monoclonal antibodies on the isolated virus. Still, it is very important to insist that water containers, like tires and plastic containers serve as reservoirs to mosquitoes and they should be emptied and corked.