An Alert System for Informing Environmental Risk of Dengue Infections

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. Ovitrap Index has been in use in many countries. This is a measurement of mosquito eggs in specified geographic location, which in turn reflects the distribution of Aedine mosquitoes, the vector for dengue. Using GIS application, an alert system was created from a synthesis of geospatial data on Ovitrap indices in Hong Kong. The inter-relationship between Ovitrap indices and temperature was made. This forms the rationale for the generation of weighted overlays to define risk levels. The weighting could be controlled to set the sensitivity of the alert system. This system can be operated at two levels, one for the general public to assist the evaluation of dengue risk in the community, and the other for professionals and academia for supporting technical analysis. The alert system offers one objective means to define risk of dengue in a society, which would not be affected by the incidence of the infection itself.

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