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GIS: A tool for monitoring and management of epidemics
Dr. C.P. Johnson
Geomatics Group, C-DAC,
Pune University Campus, Pune 411007
Tel.: (020) 5672000, Fax: (020) 5679311
johnson@cdac.ernet.in
Dr. Jasmin Johnson
Dept. of Microbiology,
B.J. Medical College, Pune 411 001
Tel.: (020) 6128000
jasminjo@hotmail.com
Abstract:
GIS provides excellent means for visualising and analysing epidemiological data, revealing trends, dependencies and inter-relationships. It can acquire, store, manage, and geographically integrate large amounts of information from different sources, programmes and sectors. GIS serves as a common platform for convergence of multi-disease surveillance activities. Standardised geo-referencing of epidemiological data facilitates structured approaches to data management. Once the basic structure is ready, it is easy to convert it to surveillance system for any other disease. Public health resources, specific diseases and other health events can be mapped in relation to their surrounding environment and existing health and social infrastructures. Such information when mapped together creates a powerful tool for monitoring and management of epidemics. GIS helps generate thematic maps that depict the intensity of a disease or vector. It can create buffer zones around selected features and then combine this information with disease incidence data to determine how many cases fall within the buffer. It can also map the impact zone of vector breeding site, where control activity needs to be strengthened. GIS can identify catchment areas of health centres and also locate suitable site for a new health facility. It can overlay different pieces of information and carry out specific calculations. GIS allows interactive queries of information contained within the map, table or graph. It permits a dynamic link between databases and maps so that data updates are automatically reflected on the maps. Dynamic maps published on the Internet assist patients in locating the most convenient health services easily. GIS can process aerial/satellite images to allow information like temperature, soil types and landuse to be easily integrated, and spatial correlations between potential risk factors and the occurrence of diseases to be determined.
Introduction
Recent advances in geographical information and mapping technologies have created new opportunities for public health administrators to enhance planning, analysis, monitoring and management of health systems. Health mapping has evolved from Dr. John Snow's cholera death mapping in mid-nineteenth century to the latest Internet-based mapping where data have been shared across the Internet. Since much of the data used and generated by health and social service agencies has a spatial dimension, geographic information system (GIS) is particularly useful to health professionals and administrators in planning and day-to-day management (Colledge et al., 1996).
A typical GIS comprises an organised collection of computer hardware, software, geographic data and personnel, designed to efficiently capture, store, update, analyse and display all forms of geographically referenced information. Each piece of information is related in the system through specific geographical coordinates (e.g. latitude and longitude) to a geographical entity (e.g. health centre, school, dam, drainage, village or state). The information can be displayed in the form of maps, graphs, charts and tables.
Despite tremendous potential of GIS, the health sector in India has not fully explored it. Majority of the health departments and research organisations in India do not have the hardware, software or trained staff that would enable them to apply GIS technology. However, the interest in GIS has increased during the late 1990s. Many health organisations, such as Malaria Research Centre, DANLEP and Vector Control Research Centre, are exploring its potential utility in medical research and disease control. In this paper, we highlight the role of GIS in monitoring and management of epidemics.
GIS and Epidemiology
Understanding the determinants of a disease, and its spread from person to person and community to community, has become increasingly global (ESRI White Paper, 1999). GIS plays a vital tool in strengthening the whole process of epidemiological surveillance information management and analysis. GIS provides excellent means for visualising and analysing epidemiological data, revealing trends, dependencies and inter-relationships that would be more difficult to discover in tabular formats. Public health resources, specific diseases and other health events can be mapped in relation to their surrounding environment and existing health and social infrastructures. Such information when mapped together creates a powerful tool for monitoring and management of diseases and public health programmes.
The underlying factors likely to lead to increased incidence of diseases, including adverse environmental, behavioural and socio-economic conditions, need to be monitored regularly. By tracking the sources of diseases and the movement of contagions, health agencies can respond more effectively to the outbreaks of epidemics by identifying populations at risk.
Software packages such as BodyViewer by GeoHealth, help medical personnel visualise clinical data. Integration of clinical information is accomplished by linking unique codes directly to a graphical representation of the human body and to the geographical location where the patient has originated (ESRI White Paper, 1999). Such geoclinical information system is a useful tool when evaluating environmental risks and exposures.
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