geographical information system (gis) in communicable ... day/session 2/gis... · •spatial...
TRANSCRIPT
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Geographical Information
System (GIS) in
Communicable Disease Control
Prof Dr Shamsul Azhar Shah
Department of Community Health
Faculty of Medicine
Universiti Kebangsaan Malaysia (UKM)
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OVERVIEW
• Introduction
• Disease Surveillance
• Emerging/Re-emerging issues
• Feature Unique to Communicable Diseases
• Factors Influencing Transmission
• GIS function
• GIS in Public Health/Epidemiology
• Usage of GIS in Communicable Diseases
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INTRODUCTION
• Populations and communities are geographically distributed and communities tend to have their own defining characteristics.
• Environment, which includes both physical (i.e., air quality, water quality, soil characteristics, radiation) , socio economic and lifestyle aspects have marked geographical variation.
• Communicable diseases - significantly affect the quality of life and the life span of all communities
– with certain parts of society being more vulnerable than others.
• Public health action prevents, limits and controls such diseases
– through disease prevention strategies and health promotion programs, including surveillance, investigation of reported cases and outbreaks, and appropriate action to prevent further spread.
• Maintenance of a strong communicable disease response is an integral part of a national strategy to maintain and improve the public health.
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DISEASE SURVEILLANCE
• Disease surveillance is an epidemiological practice
by which the spread of disease is monitored in
order to establish patterns of progression.
• The main role of disease surveillance is to
– predict
– observe
– minimize
the harm caused by outbreak, epidemic, and pandemic
situations, as well as increase our knowledge as to what
factors might contribute to such circumstances.
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EMERGING/RE-EMERGING
• Emerging infectious disease:
– An infectious disease that has newly appeared in a population or that has been known for some time but is rapidly increasing in incidence or geographic range.
• Re-emerging
– diseases are those that have been around for decades or centuries, but have come back in a different form or a different location
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SOME EXAMPLES:
EMERGING AND RE-EMERGING
EMERGING/NEWLY EMERGING
• Ebola
• Pandemic Influenza (H5N1, H1N1, MERSCOV...)
• SARS
• Nipah
• West Nile
• Mostly zoonotics
RE-EMERGING
• Tuberculosis
• Malaria
• Dengue
• Cholera
• Typhoid
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FEATURES UNIQUE TO
INFECTIOUS DISEASES
1. A case may also be a source
2. People may be immune
3. A case may be a source without being
recognized.
4. There is often a need for urgency
5. Preventive measures often have good
scientific basis.
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Agent
Host
Environment
• Age
• Sex
• Genotype
• Behaviour
• Nutritional status
• Health status
• Infectivity
• Pathogenicity
• Virulence
• Immunogenicity
• Antigenic stability
• Survival
• Weather
• Housing
• Geography
• Occupational setting
• Air quality
• Food
Factors influencing disease
transmission
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GIS FUNCTION
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WHAT IS GIS? • A special kind of information system
– Capture, store, manage, retrieve, analyse & present
spatial information
– Mainly about location
• Integrate many different types of data
• With GIS we can easily: – Draw maps and visualise spatial distributions
– Edit and alter existing data
– Accurately measure distances and areas
– Overlay maps of different areas
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Imagine an overhead projector, with a series of transparencies laid upon
it. Each transparency is about your town, drawn to the same scale, and
can therefore be integrated with the others. But each transparency deals
with a different topic: roads, places, earthquakes, census divisions, soil
landscape data, and ecological zones:
GIS - An Analogy
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The Global Positioning System
(GPS) is a system allowing to
precisely identify locations on
the Earth
Global Positioning System Device
GPS
Space Segment
Control segment
User segment
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Global Positioning System
Device
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WHAT GIS CAN HELP
PUBLIC HEALTH? • Research Tools and Planning
– Constructing mathematical models
– Service planning and optimisation
– Making predictions
• Spatial Decision Support Systems
– Infrastructure – roads, towns, services
– Census – population statistics
– Medical resource (hospitals, clinics, available beds)
• Emergency Response Systems
– Medicare records, 911 services
– disease registers systems
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GIS in Public Health
Incidence/Prevalence Spatial analysis Risk mapping
Service utilization
Cluster detection
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GIS Applications in Epidemiology
1. Data Visualisation and Exploration
2. Data Integration
3. Monitoring
4. Geostatistics and Modelling
5. Spatial Interaction and Diffusion
6. Data Sharing and Web Services
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USAGE OF GIS IN
COMMUNICABLE
DISEASE CONTROL
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DENGUE
•Vectorborne disease
•Spread by mossquitoes
(Aedes spp)
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STUDY LOCATION: PETALING JAYA AND SUBANG, MALAYSIA
Number of cases map by area
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Point/Dot
representing the
cases overlayed
with NVDI map
(normalized
difference
vegetative index)
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Dengue cases
overlayed with
LST map (Land
surface
temperature)
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Point location of dengue cases in
MPPJ and MPSJ for year 2002
Landuse Map Classification
using Landsat
Areas circled in black indicates with a high
number of dengue fever cases. The cases
were found to be mainly focused in
buildup areas.
IKONOS satellite imagery was used for point
location of cases as well as the identification
of the area type (squatter colonies, high dense
residential area & etc.) because of its 1m
spatial resolution.
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Factors of dengue transmission in Majlis Perbandaran Petaling Jaya(MPPJ) and Majlis Perbandaran Subang Jaya(MPSJ) using remote sensing and geographic information system (GIS)
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Population Density Map and Dengue
Case of Petaling Jaya (MPPJ) year
2001
Population Density Map and Dengue
Case of Petaling Jaya (MPPJ) year 2002
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Dengue
outbreak pattern
in 2002 from
Epid Week 1 to
Epid Week 52.
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BACK
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BACK
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BACK
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BACK
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BACK
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BACK
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BACK
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BACK
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Spatial statistics
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TYPHOID
•Salmonella typhi
•Transmitted via food and water
•Human host
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STUDY LOCATION: KOTA BHARU, KELANTAN, MALAYSIA
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NUMBER OF CASES BY AREA
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INCIDENCE MAP
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HOTSPOT ANALYSIS
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HOTSPOT CLUSTERS BY POPULATION CENCUS
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HOTSPOT WITH 500M BUFFER ZONE FROM RIVER
TUBERCULOSIS
•Mycobacterium tuberculosis
•Human to human
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STUDY LOCATION: KOTA BHARU, KELANTAN, MALAYSIA
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TB clusters in Kelantan, 2003-2007 by using SaTScan, Poisson model with pure space model
Clusters of pulmonary TB
Clusters of extra-pulmonary TB
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STUDY LOCATION: CHERAS, KUALA LUMPUR (2008-2012)
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CHIKUGUNYA
•Vectorborne diseases
•Transmitted by mosquitoes (Aedes spp)
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STUDY LOCATION: SELANGOR, N.SEMBILAN, PAHANG AND
JOHOR, MALAYSIA
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SEROPOSITIVE OF CHIKUGUNYA IN THE
STUDY AREA
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Red dots:
chikungunya
seropositive
Black dots:
chikungunya
seronegative
INFLUENZA
•Influenza A and B
•Human to human
•Animal to human
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STUDY LOCATION: NIIGATA, JAPAN
Address matching system
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Cases of influenza patients in 3 clinics
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Total influenza patients within 500m mesh
PAY ATTENTION NOW TO
THE NEXT FOLLOWING
SLIDES
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05-07w
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06-08w
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07-09w
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08-10w
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09-11w
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10-12w
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11-13w
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12-14w
CHALLENGES IN
IMPLEMENTATION
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What are the challenges?
• Abundance of data but incomplete (certain main
variables missing e.g. coordinates, case
confirmation)
• Not more than 5 years of data could be found (data
went missing, no back up)
• Not enough trained personnel in mapping (no
continuity, promotion to other unit)
• Not many epidemiologists trained with GIS
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Most important…
• Can it be used as a surveillance
system where we need to make
sure it is ongoing, analysed and
utilised?
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Conclusions • GIS is a relatively recent and complex
technology – which explains why it has not been used to its
full potential, especially in the health domain where it is extremely promising.
• A tool of prime importance in the surveillance and control of communicable diseases – Must be used in outbreak investigation
• Varieties of analysis could be done using GIS and different personnel need different aspect of the analysis
• We need to overcome manpower problems, data entry problems, mapping software etc.
• GIS is not a magical solution to all the difficulties regarding information in health care, but is a powerful tool capable of transforming the way with which information is dealt with.
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Thank You