ABSTRACT
An 18-year interval between a dengue virus type 1 outbreak in 1977-1979 and a dengue virus type 2 outbreak in 1997 in Santiago de Cuba, Cuba, provided a unique opportunity to evaluate risk factors for dengue disease. All patients with symptomatic dengue, including 205 cases of dengue hemorrhagic fever and 12 deaths, were adults born before the dengue virus type 1 epidemic, and nearly all (98%) experienced secondary dengue virus infections. In contrast, almost all of those who seroconverted without illness (97%) experienced primary dengue virus infection. This provides epidemiologic support for the immune enhancement theory of dengue pathogenesis. The Cuban experience suggests that immune enhancement can be seen even 20 years after the primary dengue virus infection. It also supports the contention that primary infections with dengue virus type 2 (and dengue virus type 4) are largely subclinical. These observations have implications for dengue vaccine development based on live-attenuated viruses.
Subject(s)
Dengue Virus/genetics , Disease Outbreaks , Severe Dengue/epidemiology , Adult , Age Distribution , Antibodies, Viral/immunology , Child , Cuba/epidemiology , Dengue Virus/immunology , Humans , Risk Factors , Severe Dengue/immunology , Severe Dengue/transmissionABSTRACT
The nonstructural proteins NS1 and NS3 from dengue virus are involved in the immune response during natural infection in humans. To analyze the immunogeneity of some epitopes present in NS1 and NS3 proteins from dengue virus type-4, six oligopeptides were synthesized; five from NS1 (NS1.1, NS1.2, NS1.3, NS1.4, and NS1.5) and one from NS3 (NS3.1). Peptides NS1.1, NS1.2, NS1.3, NS1.5, and NS3.1 were recognized by sera from dengue virus-infected children, suggesting that they represent exposed epitopes during natural dengue virus infection.