Dengue virus 1 and 2: Epidemiology, host–virus interactions, clinical severity and integrated control strategies

Dengue is a serious mosquito-borne viral disease caused by four antigenically distinct serotypes of the dengue virus, of which DENV-1 and DENV-2 have been found to play significant roles in outbreaks and severe disease across different geographical areas. This review discusses the epidemiology, host–virus interactions, pathogenesis, clinical manifestations, severity, vaccination, and integrated control strategies of DENV-1 and DENV-2. The relevant literature was identified by searching major scientific databases using keywords related to DENV-1, DENV-2, dengue epidemiology, pathogenesis, clinical severity, immune responses, vaccination, and vector control; studies were selected for relevance to the review's objectives. The evidence suggests that DENV-1 and DENV-2 share a number of major mechanisms in causing disease, including viral replication, innate immune modulation, endothelial dysfunction mediated by viral NS1, inflammatory response, and antibody-dependent enhancement, but that clinical outcomes are variable and may depend on viral genotype/lineage, prior dengue exposure, host immunity, age, geographical context, and study population. Furthermore, epidemiological and clinical studies have been unable to rank the severity of DENV-1 and DENV-2, as both serotypes have been reported to cause severe dengue across different settings and conditions. The available data thus suggest that the severity of dengue is multifactorial and not serotype-dependent. Ongoing comparative studies that integrate viral genetics, host immune responses, epidemiology, vaccines, and vector control are needed to enhance serotype-specific dengue prevention and clinical management.