DENGUE, YELLOW-FEVER, AND RABIES

Important new findings on the dengue viruses include continued evidence that dengue hemorrhagic fever/dengue shock syndrome is caused by a second infection but only with a virus of southeast Asian origin; the dengue viruses that cause both mild and severe disease are genetically identical; tumor necrosis factor circulates at relatively high levels during the shock stage of dengue while malnutrition protects children from dengue hemorrhagic fever/dengue shock syndrome. Yellow fever vaccine was found to cross the placental barrier but not to cause congenital disorders in infected infants. Genetic studies show that art American rabies viruses originated from strains brought to the New World by European dogs.