Disease Surveillance and Monitoring using GIS  Rajiv Gupta Associate Professor, Civil Engg. Group, Birla Institute of Technology and Science, Pilani (Raj.), 333031, India, Ph.No:091- 01596-245030 (R); 01596-245073*277, Fax: 91-1596-244183. email: rajiv@bits-pilani.ac.in  R.Shriram Under graduate student, Birla Institute of Technology and Science (BITS), Pilani (Raj.), 333 031, India email: shriramramartanam@yahoo.co.in, f2000667@bits-pilani.ac.in Abstract: Epidemiology is an independent branch of medicine studying aetiology and spreading of infectious diseases in an human community and is aimed at prevention, control, and final eradication of these diseases. The combination of routes by which the pathogenic microorganisms are transmitted from an infected microorganism to a healthy one is called the mechanism of infection transmission. An infection process is the interaction of a pathogenic microorganism with a macro organism under certain environmental and social conditions. Infectious diseases are classed as anthroponoses (source: man), zoonoses (source: animal), and anthropozoonoses (sources: man and animal). For the epidemic to break out it is not sufficient to have a source of infection alone, but also an appropriate mechanism of transmission. Four mechanisms of infection transmission are distinguished: (1)faecal-oral route; (2)air-borne; (3)transmissive; (4)contact and the main factors involved in transmission of infection are: air, water, foods, soil, and arthropods. An infection process is the interaction of a pathogenic microorganism with a macro organism under certain environmental and social conditions. Living inside its host, the microorganism persists for a definite period of time then moves to another host via a corresponding transmission mechanism. Hence, three obligatory factors are necessary for the onset and continuous course of an epidemic process: source of pathogenic microorganism, the mechanism of their transmission, and microorganisms susceptible to infection. Agents involved in new and reemergent infections cross taxonomic lines to include viruses, bacteria, fungi, protozoa, and helminthes; Human activities are the most potent factors driving disease emergence; Main factors are: Social, economic, political, climatic, technologic, environmental factors, shape, disease patterns and influence emergence Infectious diseases that are responsive to climate can be divided into two groups. The first group comprises those diseases for which there are clearly documented links between incidence and climate and weather factors. This group is primarily composed of vectorborne diseases, including malaria, hantavirus pulmonary syndrome, dengue, and various forms of viral encephalitis. The second group comprises diseases whose incidence is cyclical, thereby suggesting a link to climate, but for which the potential mechanisms linking climate factors to incidence are either unknown or only tentatively established. Campylobacteriosis and cholera are notable examples of diseases in this category, but recent research on cholera epidemiological patterns has demonstrated a clear association between sea-surface temperature and cholera incidence. Microorganisms carried by vectors, such as mosquitoes, ticks, and other blood-sucking arthropods, are strongly influenced by temperature of the microenvironment within their cold-blooded vector hosts. The survival rates of vectors and the rates of multiplication and transmission of the microorganisms that infect them are temperature dependent. The physiological relationship between temperature and the malaria parasite and its mosquito vector exemplifies this dependency. Precipitation, especially in the form of rainfall, can affect disease transmission via the effects of normal, as well as severe (i.e., flooding and drought), events on vector populations. Flooding can influence disease transmission in a number of ways, most notably by increasing run-off and disturbing breeding grounds and habitats. The drowning of rodents that are reservoirs for diseases can lead to increased transmission by increasing human contact with contaminated water. The potential for variations in wind and wind patterns to promote infectious diseases is a generally neglected aspect of climate-human health interactions. Sea-surface temperature, height, and concentration of nutrients in seawater are associated with cholera incidence GIS provides excellent means for visualizing and analyzing epidemiological data, revealing trends, dependencies and inter-relationships. GIS serves as a common platform for convergence of multi-disease surveillance activities. 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 us out in many ways. These include the following applications.
|