An Alert System for Informing Environmental Risk of Dengue Infections

Abstract

Dengue is a mosquito-borne infection the incidence of which varies with the environment and climate. Knowingly, the reported incidence of dengue is an insensitive indicator of infection risk in a locality. The Ovitrap Index has been in use in many countries. This index is a measurement of mosquito eggs in specified geographic locations which, in turn, reflects the distribution of Aedine mosquitoes, the vector for dengue. An alert system, founded on the Geographic Information System (GIS) technology, was created from a synthesis of geospatial data on ovitrap indices in Hong Kong. The inter-relationship between ovitrap indices and temperature was studied. This inference forms the rationale for the generation of weighted overlays to define risk levels. The weighting can be adjusted to set the sensitivity of the alert system. The system is operational at two levels: (1) for the general public to assist in the evaluation of dengue risk in the community, and (2) for professionals and academia in undertaking technical analysis. The alert system offers one objective means to defining the risk of dengue in a society, which would not be affected by the incidence of the infection itself.