Human dendritic cells as targets of dengue virus infection.

Dengue virus infections are an emerging global threat. Severe dengue infection is manifested as dengue hemorrhagic fever and dengue shock syndrome, both of which can be fatal complications. Factors predisposing to complicated disease and pathogenesis of severe infections are discussed.

Haiti: absence of dengue hemorrhagic fever despite hyperendemic dengue virus transmission.

In 1994-1996, 185 strains of dengue (DEN) virus types 1, 2, and 4 were recovered from febrile United States and other United Nations military personnel in Haiti. We wondered whether risk factors for dengue hemorrhagic fever (DHF) existed and, if so, were DHF cases occurring among Haitian children. Dengue transmission rates were studied in 210 school children (6-13 years old) resident in Carrefour Borough, Port-au-Prince, Haiti.

Detection of dengue viral RNA using a nucleic acid sequence-based amplification assay.

Faster techniques are needed for the early diagnosis of dengue fever and dengue hemorrhagic fever during the acute viremic phase of infection. An isothermal nucleic acid sequence-based amplification (NASBA) assay was optimized to amplify viral RNA of all four dengue virus serotypes by a set of universal primers and to type the amplified products by serotype-specific capture probes. The NASBA assay involved the use of silica to extract viral nucleic acid, which was amplified without thermocycling.

Human skin Langerhans cells are targets of dengue virus infection.

Dengue virus (DV), an arthropod-borne flavivirus, causes a febrile illness for which there is no antiviral treatment and no vaccine. Macrophages are important in dengue pathogenesis; however, the initial target cell for DV infection remains unknown. As DV is introduced into human skin by mosquitoes of the genus Aedes, we undertook experiments to determine whether human dendritic cells (DCs) were permissive for the growth of DV.

Immunogenicity of live attenuated SA14-14-2 Japanese encephalitis vaccine--a comparison of 1- and 3-month immunization schedules.

Live attenuated SA14-14-2 Japanese encephalitis (JE) vaccine has been safe and effective in >100 million immunized children, but its current administration schedule of two doses given a year apart does not lend itself to inclusion in established Expanded Program of Immunization (EPI) schedules of childhood immunization. Immune responses to immunization at shorter intervals were compared in middle-school-aged children immunized with two doses separated by 1 month (n = 116) or 2.5 months (n = 115).