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.