ECOMORE 2 project

The main objective of ECOMORE 2 was to gather different sources of information (disease surveillance; entomologic indicators; socio-demographic data; meteo/ climatic data…) to develop a multi-data modeling system to predict future dengue epidemics. In this context, the dengue surveillance system provided a core source of information, including GPS coordinates of dengue confirmed cases for real-time mapping in the Vientiane Capital. Socio-demographic data from the last census and satellite pictures were used to characterize the city. In addition, weather and environmental parameters were integrated into the analysis to determine the impact of climatic and environmental conditions on arbovirus transmission. We observed a delta of 11% in the prevalence rates between the urbanized parts of the Vientiane capital in comparison with the rural ones. This delta has no impact on the incidence of dengue, but it could impact the ecology of dengue vectors.

In parallel, we conducted a seroprevalence study of dengue in the target population of Vientiane Capital using discriminant ELISA for typing arbovirus antibodies (DELTAa). We observed that 66.3% of the population have antibodies against dengue when tested using a standard dengue IgG ELISA. When measuring the antibody affinity using DELTAa assay with a threshold of 60%, the seroprevalence rate dropped to 21.8%. In addition, of the 254 tested samples serotyping, by measuring the antibody affinity using DELTAa, 16.9% displayed mono-specific anti-DENV antibodies. Dengue seroprevalence rates based on high affinity antibodies was found to be limited in the Vientiane Capital with an increase with age (Figure 4)