Remote sensing is defined as the scientific and computerized technique of gathering images (or data) of the earth’s surface from the space (satellites) and transforming same into maps that are used to investigate the co-distribution of a disease within a defined human population. Geographical information system (GIS) is a data-based management system that organizes and displays digital map images from remote sensing in order to analyze the relationships between mapped features from the mapping. While remote sensing allows the investigation of disease co-distribution with environmental variables at various spatial scales as it integrates data from remote sensors based on space platforms within GISs, GISs are computer software packages that permits the capture, storage, analysis and display of any type of geographical data or image as it relates to a disease in a particular population. Remote sensing and geographical information system (GIS) are both emerging technologies (epidemiological disease mapping tools) which are applied in the field of epidemiology to contain disease emergence and spread within a given population.
Remote sensing and GIS includes the mapping of a disease in a population with a view to determining the socioeconomic and environmental factors implicated in the infection. Both remote sensing and GIS play vital roles in the study and control of a disease in any given population; and their proper use can help to checkmate and control some of the child-killer diseases (Figure 28.2) in some parts of the world especially in some developing countries where access to quality healthcare and environmental hygiene conditions are still in a pitiable state. It is noteworthy that the principle of remote sensing and GIS was first used in the field of epidemiology by John Snow (the father of epidemiology), who demonstrated successfully how the cholera disease was distributed within London metropolis between 1849 and 1854 through contaminated water. John Snow used the information he gathered (from both sufferers and non-sufferers of the cholera disease as at the time) to develop a “spot map” which enabled him to determine the distribution of disease cases in the affected population. Snow’s meticulous work showed that epidemiological data could be used to determine disease emergence and spread. His groundbreaking discovery was used to implement appropriate public health interventions to prevent the re-occurrence of the disease; and his thorough and independent research helped influenced public health policy in London, England and even till date.
The technology of remote sensing and GIS has been used to map various microbial diseases across different parts of the world. Some of these diseases that have been mapped using GIS and remote sensing include the Rift Valley fever in Kenya, schistosomiasis in human and livestock in the southeastern USA, location of Plasmodium and its vector in Asia and Mexico, African trypanosomiasis, Onchocerciasis amongst other diseases. Most child killer diseases including malaria and pneumonia amongst others can also be properly tracked by GIS and remote sensing and this could help alleviate the morbidity and mortality rate of these diseases amongst children populations (Figure 1). Data from GIS and remote sensing can be used to aid the design and implementation of control programs for a given disease. They also help scientists to gain an understanding regarding the spatial distribution of a particular disease within a given geographical location.
Disease tracking (as exemplified by the GIS and remote sensing technique) in this century is critical to sustainable development especially as it pertains to the health of the general public owing to the emergence and re-emergence of some infectious diseases (e.g. ebola virus disease and lassa fever) which has spread in some parts of the world and have caused innumerable hardship to people (Figure 2). When infectious diseases are properly tracked, their spreading patterns and reservoirs can be decoded and exploited by both epidemiologists and other public health practitioners for their complete control, prevention or eradication in the population where the disease is occurring.
Figure 1: Pie chart showing the percentage distribution of causes of death in children under the age of five (5) years. These data are from the 2013 World Health Statistics, which is conducted by the World Health Organization (WHO). WHO
Figure 2: Demographic distribution of some emerging and re-emerging infectious diseases across the world. These data are from “A Report from the American Academy of Microbiology” on: Clinical Microbiology in the 21st Century, which is conducted by the American Society for Microbiology (ASM), Washington DC.
Worldwide, the human population is continually faced with both new infectious diseases and the recurrence of older infectious diseases such as tuberculosis and yellow fever among others which were once thought to be conquered by medical science advancement. These infectious diseases which also include drug-resistant infections has increased in frequency in human population in the recent past, and they also have the likelihood of also increasing in their occurrence in the near future if nothing is done to contain them. The emergence and spread of these new reemerging infectious diseases have been certainly propagated following the many features of the contemporary world including increased globalization, travel, climatic changes, technological advancements, wars, agricultural practices, economic forces and the threat of bioterrorism in particular. In addition, the mutational changes that occur in pathogens, their vectors and susceptible hosts in particular also encourage the outburst that allows previously controlled infectious diseases to reemerge. Emerging and reemerging infectious diseases and the microbial agents responsible for their occurrence are a grave global public health concern, thus it is vital that these diseases are contained through holistic global health interventional programs and surveillances in order to detect these diseases and ensure a better health for all.
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