Development of a geographic information-driven real-time surveillance system for disease surveillance.

Abstract

To respond to emerging public health threats such as West Nile virus, an advanced geographic information systems (GIS) -driven Web-based real-time surveillance system was developed to serve the National West Nile virus dead bird surveillance programme in Canada. The development of this system uses real-time Web GIS technologies and services to enhance conventional real-time surveillance systems based on real-time GIS requirements. The system has three modules: QuickTrack, QuickMap and QuickManage. QuickTrack is the real-time surveillance module that supports data collection, edit and transfer. QuickMap is the real-time Web GIS module that provides comprehensive real-time GIS supports and services in public health surveillance and information sharing. The QuickManage module is a Web-based system management package used to manage the entire system. This system offers an effective approach to enhance real-time public health surveillance systems by integrating real-time Web GIS technologies and services. The system demonstrates that real-time Web GIS technologies can play an important role in enhancing public health surveillance systems.

Full text

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Veterinaria Italiana, 43 (3), 451-461
© IZS A&M 2007 www.izs.it/vet_italiana Vol. 43 (3), Vet Ital
451
Development of a geographic information-driven
real-time surveillance system for disease surveillance
Jiangping Shuai(1), Peter Buck(2), Caroline Chevalier(2) & Paul Sockett(2)
Summary
To respond to emerging public health threats
such as West Nile virus, an advanced
geographic information systems (GIS)-driven
Web-based real-time surveillance system was
developed to serve the National West Nile
virus dead bird surveillance programme in
Canada. The development of this system uses
real-time Web GIS technologies and services to
enhance conventional real-time surveillance
systems based on real-time GIS requirements.
The system has three modules: QuickTrack,
QuickMap and QuickManage. QuickTrack is
the real-time surveillance
supports data collection, edit and transfer.
QuickMap is the real-time Web GIS module
that provides comprehensive real-time GIS
supports and services in public health
surveillance and information sharing. The
QuickManage module is a Web-based system
management package used to manage the
entire system. This system offers an effective
approach to enhance real-time public health
surveillance systems by integrating real-time
Web GIS technologies and services. The
system demonstrates that real-time Web GIS
technologies can play an important role in
enhancing public health surveillance systems.
module that
Keywords
Canada, Geographic information systems,
Real-time, Surveillance, Web, West Nile virus.
Sviluppo di un sistema di
sorveglianza in tempo reale
delle malattie basato sulle
informazioni geografiche
Riassunto
Per rispondere a minacce emergenti per la salute
pubblica, come il virus West Nile, è stato
sviluppato in Canada un sistema avanzato di
sorveglianza in tempo reale via Web, basato su
sistemi d’informazione geografici avanzati (GIS:
geographic information systems) per gestire il
programma di sorveglianza nazionale della West
Nile col controllo dei volatili morti. Lo sviluppo di
tale sistema utilizza tecnologie e servizi GIS via
Web in tempo reale per intensificare i sistemi
convenzionali di sorveglianza in tempo reale basati
su requisiti GIS. Il sistema ha tre moduli:
QuickTrack, QuickMap
QuickTrack è un modulo di sorveglianza in tempo
reale che si occupa di raccogliere, pubblicare e
trasferire i dati. QuickMap è il modulo GIS su Web
in tempo reale che fornisce esaurienti supporti e
servizi GIS in tempo reale nella sorveglianza della
salute pubblica e nella
informazioni. Il modulo QuickManage è un
pacchetto di gestione di sistemi su Web utilizzato
per gestire l’intero sistema. Tale sistema offre un
approccio efficace per rafforzare i sistemi di
sorveglianza della salute pubblica in tempo reale
mediante l’integrazione di tecnologie e servizi GIS
via Web in tempo reale. Inoltre esso dimostra che le
tecnologie GIS via Web in tempo reale possono
e QuickManage.
condivisione delle

(1) Foodborne, Waterborne and Zoonotic Infections Division, Centre for Infectious Disease Prevention and Control,
Public Health Agency of Canada, 255 Woodlawn Road West, Unit 120, Guelph, Ontario N1H 8J1, Canada
jiangping_shuai@phac-aspc.gc.ca
(2) Foodborne, Waterborne and Zoonotic Infections Division, Centre for Infectious Disease Prevention and Control,
Public Health Agency of Canada, Tunney’s Pasture, Building No. 6, Ottawa, Ontario K1A 0L2, Canada

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Development of a geographic information-driven
real-time surveillance system for disease surveillance
Jiangping Shuai, Peter Buck, Caroline Chevalier & Paul Sockett
452
Vol. 43 (3), Vet Ital www.izs.it/vet_italiana © IZS A&M 2007
giocare un ruolo importante nell’incremento dei
sistemi di sorveglianza della salute pubblica.
Parole chiave
Canada,
Sorveglianza, Tempo reale, Web, West Nile.
Sistema informativo geografico,
Introduction
In August 2001, West Nile virus activity was
first reported in Canada, with the discovery of
the virus in dead birds and mosquito pools in
southern Ontario. In 2002, Canada reported its
first confirmed human cases in areas of
Ontario and Quebec. The virus was also found
in birds, horses and mosquitoes in Manitoba,
Nova Scotia, Ontario,
Saskatchewan. Two people in Alberta were
infected and infection was thought to be
related to travel. A total of 1 495 cases of West
Nile virus and asymptomatic infections were
reported in humans in 2003, 26 cases in 2004
and 238 cases in 2005 (11). In 2006, five
provinces (Alberta, Manitoba, Ontario, Quebec
and Saskatchewan) confirmed cases of human
infection (13).
Quebec and
Dead bird surveillance plays an important role
in West Nile virus surveillance as it helps
explain the distribution of West Nile virus
activity. Yaremych et al. found that 90.5% of
the dead American crows were confirmed
positive for West Nile virus from May to
October 2002 in Illinois (16). In 2000, New York
State, Bernard et al. reported that 47% of dead
American crows were tested positive for West
Nile virus (1). Watson et al. found a spatial
association between early-season crow deaths
and human West Nile virus infection cases
(14). Mostashari et al. reported that dead bird
data could be used for early warning of West
Nile virus activity in small areas. Jurisdictions
could also develop early larval control
programmes and prioritise
surveillance based on spatial-temporal cluster
analysis using dead bird data (9).
regions for
Geographic information systems (GIS) have
been used widely in public health by the
World Health Organization (WHO) that
established a GIS for leprosy elimination (15)
and by the Centers for Disease Control and
Prevention (CDC) that developed a GIS and
public health website (2). Open source GIS
have also been used (3, 8). In Canada, GIS is
used for a wide variety of public health
surveillance systems, such as the disease
surveillance online website which provides
mapping and other services for cancer,
cardiovascular diseases,
diseases, notifiable diseases
surveillance (10).
major chronic
injury and
Since the introduction of the national West
Nile virus surveillance programme and
subsequent requirement for GIS support in the
Public Health Agency of Canada, the format of
GIS applications has evolved constantly. In
2001, ArcView™ was used to create and export
static image maps that were posted on the
website. In 2002, html ImageMapper™ was
introduced to transform ArcView™ maps and
data into an interactive map website. In 2003
and 2004, a new interactive map website was
developed using MapServer™ for which an
automated ArcView™ application produced
ten daily static maps. While this innovative
approach reduces workload and file transfer
volumes, the original static maps created in
2001 also remain functional. As the static and
interactive maps operate
operation costs have increased. The preferred
option is to streamline these applications and
systems to automate any manual GIS
operations.
independently,
Between 2001 and 2004, the GIS elements for
West Nile virus surveillance have continued to
play a crucial role. New surveillance methods
and data sources have been introduced
enabling a georeferencing
improves data quality and location accuracy.
Funding opportunities, such as GeoConnections
funding for sharing spatial data through the
Canadian geospatial data infrastructure in the
field of public health (4) have also arisen. The
benefits of using GIS in other passive and
active surveillance programmes have been
discussed. To address these GIS needs and to
streamline national
surveillance systems, a Web-based integrated
real-time surveillance system was proposed in
2003 and the development of this system was
completed in 2004.
solution that
West Nile virus

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Jiangping Shuai, Peter Buck, Caroline Chevalier & Paul Sockett

Development of a geographic information-driven
real-time surveillance system for disease surveillance
© IZS A&M 2007 www.izs.it/vet_italiana Vol. 43 (3), Vet Ital
453
Materials and methods
The design of the real-time Web GIS
technologies and the integration with a Web-
based real-time surveillance system was based
on the requirements of the national West Nile
virus dead bird surveillance programme.
During the development of this GIS-driven
real-time surveillance system for disease
surveillance, two important steps were taken
in the design and integration process, namely:
to determine the GIS requirements for a real-
time surveillance system and to set the
guidelines of GIS technologies development.
Determination of geographic
information system requirements
From 2001 to 2004, there has been an
increasing demand for GIS capacities as part of
West Nile virus surveillance programmes.
These needs included the quality improvement
of spatial data, automation of spatial data
generation, capacity to allow end-users to
produce maps for any date, addition of
security control in incident data, additional
methods to generate
different location information,
generation of static maps, more interactive
Web mapping functions, GIS support in data
collection and editing and the integration of
GIS operations in surveillance operations.
coordinates using
automatic
Based on the analysis of the objectives of West
Nile virus surveillance and the increasing GIS
needs to serve this surveillance programme,
five major GIS requirements were identified
for this system to serve national West Nile
virus dead bird real-time surveillance, as
follows:
? Integration. In the past, maintaining a
separate real-time
surveillance system increased costs. In this
system, GIS capacities and components
needed to be fully integrated with real-time
surveillance system to make the entire
system more efficient and accessible for
internal and external users. The real-time
GIS components would also need to improve
surveillance data collection and data editing.
? Data quality improvement. GIS was needed to
improve the quality of spatial data in
surveillance data collection. In dead bird
GIS system and
surveillance, geo-referencing was required to
identify bird location. A variety of location
information (street address, postal code, GPS
reading, mapbook
description) was reported to the surveillance
system based on
reporting methods. All the information was
used to generate coordinates. GIS was also
used also for data validation when data
recorded were not consistent.
? Visualisation. Visualisation is an important
contribution of real-time Web GIS for a
public health surveillance system. In this
system, four types of visualisation were
required, namely: the first is represented by
maps concerning the spatial pattern of virus,
the hotspots of virus activities and spatial
clustering of virus activities in birds. These
maps include bird location point maps and
aggregated maps
confirmed positive birds in each health unit).
The second is the time series map (daily,
weekly, monthly or yearly). The third is the
ad hoc map that users can create from the
website by defining any specific periods of
time during the surveillance season. The
fourth is a map that is suitable for reports,
which include legends, statistics, logos,
inserts and titles.
? Data security and confidentiality. A security
mechanism was developed to protect the
privacy of individuals or communities.
Guarded by this mechanism, surveillance
data in the map services could not be
downloaded by any other GIS applications.
? Spatial data sharing. Sharing various spatial
data between different
programmes and
providers facilitates decision-making. The
open geospatial consortium (OGC®) Web
mapping service (WMS) standard has
enabled GIS applications to share and
distribute map-like
information in a distributed network (8). In
Canada, the federal
developed a Canadian Geospatial Data
Infrastructure Programme (CGDI) to enable
safe sharing of reliable geospatial data
information across jurisdictions and enable
collaborative and timely decision-making (4).
and legal land
different provincial
(tested birds and
surveillance
spatial other data
views of spatial
government has

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Development of a geographic information-driven
real-time surveillance system for disease surveillance
Jiangping Shuai, Peter Buck, Caroline Chevalier & Paul Sockett
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Vol. 43 (3), Vet Ital www.izs.it/vet_italiana © IZS A&M 2007
This system has developed the capacities to
access the rich WMS data sources through
the CGDI WMS technical standards (5). The
system also created a WMS data source to
provide national West Nile virus dead bird
surveillance information to the public.
Development guidelines for the
QuickMap module
In this system, all the GIS components have
been encapsulated in the QuickMap module.
QuickMap has been developed to meet
immediate GIS needs in national West Nile
virus dead bird surveillance as well as to serve
future zoonotic disease
programmes. Hence, four guidelines have
been identified for the development of
QuickMap, as follows:
? Real-time. The GIS capacities should provide
real-time support for recording and editing
of surveillance data. Whenever new data is
entered into the system or existing data is
edited, the geo-referencing and spatial
validation processes
matically. Visualisation of surveillance data
should also be real-time.
surveillance data is recorded into the
database, all maps and spatial queries are
updated immediately. Static maps and WMS
data reflect the most recent data at the time
of updates. New technologies have been
developed for ad hoc maps in which date
spans are defined by the users on the fly.
? Web-based configuration. In this system, the
GIS surveillance links and interactions can be
edited from a Web-based configuration page.
This has provided a convenient way to
update system parameters, such as static
map production schedules, ArcIMS™ service
names, colour of the thematic maps, geo-
coding services and MWS resources.
? Automation of GIS functions. Geo-reference
and spatial validation functions have been
developed to run automatically. If users
provide multiple location information, the
system will automatically
predefined order to generate coordinates and
check if it is spatially valid. Static maps,
point shapefiles and WMS updates are
operated automatically by the server. This
surveillance
commence auto-
Once the
follow a
design
maintenance costs.
? Reusability and scalability. The GIS functions
and Java classes of the systems should be
able to serve other surveillance programmes
in the future, as needs arise. The links
between the real-time surveillance module
and the real-time GIS module should be not
hard-coded, so that system administrators
can adjust Web mapping and modify queries
for other surveillance programmes. The
system is also scalable and can be deployed
to one server (for a small user group), or to
three serves (Web GIS servers, database
server and Web/application server) for larger
user groups.
has reduced operation and
Results
As mentioned earlier, the integrated real-time
West Nile virus dead bird surveillance system
has three modules: QuickTrack, QuickMap
and QuickManage. The three modules have
been integrated seamlessly (Fig. 1). The major
components of these three modules are listed
in Table I. The system is a J2EE application.
The functionality of the application is
separated along different tiers to provide a
separation of responsibilities. The Web tier
uses the Struts framework. The business tier is
based on the Spring Framework™ to manage
business objects because it can effectively
organise middle tier objects. Spring framework
takes care of plumbing and thus helps to
reduce development and maintenance efforts.
The data tier is developed using iBatis™
because of the simplicity of iBatis™ data
mapper over object relational mapping tools.
The system uses ArcIMS™ as the geospatial
processing and mapping engine, MapServer™
as the WMS engine, and Oracle® as the
database engine. Apache™ and Tomcat™ are
used as Web application servers because they
are open-source and reliable. The system uses
Struts to implement
Currently, the public website supports English
and French. However it could support other
languages as required.
internationalisation.
This system has a public-internal infra-
structure so one system serves both the public

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Jiangping Shuai, Peter Buck, Caroline Chevalier & Paul Sockett

Development of a geographic information-driven
real-time surveillance system for disease surveillance
© IZS A&M 2007 www.izs.it/vet_italiana Vol. 43 (3), Vet Ital
455
QuickManageQuickManage
Data ETLData ETL
Data entryData entry
Aspatial data fieldsAspatial data fields Validation Validation
Database Database
Spatial data fieldsSpatial data fields
QuickMap QuickMap
Georeferencing Georeferencing
Spatial validationSpatial validation
Query QueryEditEdit SearchSearch
Real-time mapReal-time map
Static mapStatic map
OGC mapOGC map
QuickTrackQuickTrack

ETL
OGC open geospatial consortium
extraction, transformation and loading
Figure 1
System modules and processes
Table I
System modules and components list
Modules Component list
QuickTrack Incident data reporting
Incident data editing
Incident data search
Data transfer ETL
Aggregated data query
QuickMap Geo-referencing
Spatial validation
Real-time interactive map
Real-time GIS and real-time
surveillance data link
Web GIS clients
GIS in QuickTrack
Static map generation, storage
and retrieval
Time-series maps
OGC WMS access
OGC WMS services
Point shapefile generation
QuickManage System configuration
Static map schedules
Group management
User management
Session management
Embargo management
WMS management
Geo-coding management
ETL
GIS
OGC open geospatial consortium
WMS Web mapping service
extraction, transformation and loading
geographic information system
and the internal sites. This approach has
streamlined system management and reduced
maintenance cost. Public users can access the
public section. Registered users can access the
internal part after logging in. The real-time
map and data query pages use the same page
for both the public and internal parts.
However, if a user is not logged in, a portion of
these pages is neither visible nor accessible.
The system is flexible using this mechanism.
Currently it is deployed with integrated public
and internal sites, but can also be hosted as a
public system only or as an internal system on
its own by changing the setting in an xml file.
This might be useful if an organisation has
already set up a surveillance system and just
needs real-time GIS functions. The GIS
functions of this system can be added to its
surveillance system, connected to the database
and real-time maps can be generated.
The system has replaced the old desktop GIS-
based west Nile virus dead bird surveillance
system and has been established to serve
national West Nile virus dead bird real-time
surveillance since May 2005 (12).
QuickTrack module
QuickTrack is the real-time surveillance
module of this system. It provides real-time