Tele-Epidemiology: Advancing the Application of Earth Observation to Public Health Issues in Canada

Stéphanie Brazeau1, Guy Aubé2, Patricia Turgeon1, Serge-Olivier Kotchi1, Pascal Michel1

1Public Health Agency of Canada, Public Health Risk Sciences Division, Saint-Hyacinthe, Québec, Canada, J2S 7C6
2Canadian Space Agency, Earth Observation Applications and Utilizations, St-Hubert, Québec, Canada, J3Y 8Y9

The emergence of zoonotic diseases is ranking highly among public health issues that the World Health Organization, World Organisation for Animal Health, and numerous national organizations, companies and universities are attempting to address. In order to mitigate these types of health risks, they are adopting a multi-sectorial approach of collaboration known as the One World One Health approach.

The Challenge: Protecting Canadians from Illness

In today’s fast changing world, public health is facing many challenges in the prevention and the control of various emerging diseases and chronic conditions. Many of these health conditions arise from a sustained interaction between evolving human populations (change in demography, migrations and travels) and the environment. Zoonotic diseases are infections that can be acquired through contact between animals and humans. According to World Health Organization, at least 61 percent of all human pathogens are zoonotic, and have represented 75 percent of all emerging pathogens during the past decade [1, 2]. The emergence of zoonotic diseases, such as avian influenza (H5N1, H1N1, H5N9), new coronavirus (MERS-Cov), the West Nile virus, Lyme disease, Ebola virus, and malaria, is ranking highly among the public health issues that the World Health Organization (WHO), the World Organisation for Animal Health (OIE) as well as numerous national organizations, companies and universities are attempting to address. In order to mitigate these type of health risks they are adopting a multi-sectorial approach of collaboration known as the One Health approach [3, 4].

Can Earth Observation be a game changer in public health?

Managing key public health issues require solid evidence-based knowledge. However, obtaining the necessary data on environmental health determinants constitutes a major challenge because of the large territory to cover. In fact, obtaining those data from field campaigns would require an unreasonable amount of resources. Fortunately, this is where Earth Observation (EO) images can step in and provide a contribution. Data from population or environmental determinants may be derived from EO images, particularly in regard to the impact of natural or anthropogenic ecosystem changes. Operationally, EO images have demonstrated their usefulness in the prevention and control of persistent and new diseases. They provide important wide and near-range geo-spatial information that can fuel research, improve monitoring and risk assessment for public health and guide intervention measures and disease control; they can also be useful in the preparation and response to emergencies; and they can help improve health security by reducing risks concerning the introduction of infectious disease (e.g., new avian influenza). Space-based EO technologies and know-how both contribute to producing unique data sets and critical information at synoptic as well as detailed spatial and temporal scales. Thus, the EO satellite data and products can be advantageous in several ways, including availability of different scales and wide-spread coverage, monitoring capability and rapid acquisition, costs effectiveness, as well as data quality and data continuity.

Public health issues are becoming increasingly complex, challenging the drive for innovation, motivating knowledge exploration, and fostering the development of expertise and partnerships. In Canada, EO has an opportunity to enhance public health-related knowledge and capacity to investigate diseases across a vast territory of more than 10 million square kilometers, including in the North. In doing so, the Canadian government can rely on access to RADARSAT-2 images through the Canadian Space Agency (CSA).

Since the 1990s, space-based EO technologies have been integrated into epidemiology and public health domains [5,6]. EO can play an important role in the decision-making process in public health, and the recent methodological approach resulting from this integration is valued by experts working on emerging and re-emerging infectious diseases in Canada. This approach is now known as tele-epidemiology.

How Can Earth Observation Enhance Public Health Capacity Through Tele-epidemiology?

Tele-epidemiology is a recent discipline combining epidemiology and space technology applied to human and animal health. This discipline allows the spatial and the temporal study of events affecting the health or disease processes. It involves the monitoring and the assessment of the distribution of animal and human illnesses strongly linked to climatic and environmental variations. [6].

Outline of interlocking elements and domains crucial to the emerging discipline of tele-epidemiology [12] Image Credit: CSA / ÆRDE, 2014.

Outline of interlocking elements and domains crucial to the emerging discipline of tele-epidemiology [12]
Image Credit: CSA / ÆRDE, 2014.

Tele-epidemiology is particularly interesting for the study and monitoring of emerging and re-emerging vector-borne diseases, since these involve the transmission of viruses or bacteria by vectors (insects, invertebrates, and mammals) whose population and movements are often influenced by environmental characteristics. Tele-epidemiology is then used to model the spread of disease and map the associated risks from vector-ecology knowledge affected by and following environmental changes (e.g., Lyme, Malaria, Eastern Equine Encephalitis, etc.). The analysis of EO images allows rapid identification of specific sites that can be used for field validation of the presence of a vector infected by a disease and the enhancement of active disease surveillance, as is the case for Lyme disease in Canada [7].

Tele-epidemiology also has recently found usefulness in the study of bacteria contaminating lakes and thus representing a risk to bathers. The use of geospatial technologies and EO images is useful to characterize the spatial and temporal variability of environmental determinants involved in microbial contamination of recreational lakes.  Even if bacteria are invisible to the human eye and to satellites, it is possible from space to characterize the sources of contamination and the determinants involved in transport and transmission (agriculture, urban areas, etc.). This risk assessment is feasible with the use of geospatial tools and through the integration of factors involved in microbial contamination, providing the information necessary for decision-making, management of public health surveillance, and control of diseases [8, 10] .

Partnerships for Better Health Decision-Making Processes in Canada

The Public Health Agency of Canada (PHAC) and the health community are exploring new initiatives with national and international partners, such as the Canadian Space Agency (CSA), the World Health Organization (WHO) and the United Nations (UN).  These partnerships are advancing the application of EO, monitoring and forecasting systems to health decision-making processes. In particular, they provide a solid base for the (1) development of tele-epidemiology EO applications (i.e., infectious and vector-borne diseases, ecology and behavior, water and air quality); (2) understanding of ecosystems changes that can lead to the emergence of diseases; and (3) integration and fusion of geospatial, medical and socio-economic data for health care decision support systems [9].

Since 2000, the Earth Observation Applications and Utilizations division of the CSA has managed EO-specific programs and projects. Efforts to date have focused on the utilization of radar and optical EO data, and on integrating the satellite data into environmental information systems related to water, agriculture, energy, climate, weather, ecosystems, biodiversity, security, and others. The CSA has worked with other government departments, with industry and with research institutions across Canada to develop and implement a number of health- and environment-related monitoring activities.

As an example, PHAC has recently completed a project through the CSA Government Related Initiatives Program (GRIP) to assess the benefit and usefulness of satellite data for monitoring and managing foodborne pathogens associated with recreational waters. EO-based methods and measurements were integrated into statistical models to assess the average contamination level of recreational beaches in southern Quebec [10, 12]. Data from various EO satellites, such as RADARSAT-2, Envisat/MERIS, Landsat-5, MODIS, AVHRR, SPOT-5, GeoEye-1 and Worldview-2 were used in order to better characterize the surrounding land use and environmental determinants. The project allowed PHAC to identify farming and urban activities as having the main influence on the microbiological quality of recreational waters in terms of fecal contamination levels from foodborne pathogens [10-11].

Tracking foodborne pathogens contamination in water from the source with EO images. Image Credit: PHAC, 2013.

Tracking foodborne pathogens contamination in water from the source with EO images. Image Credit: PHAC, 2013.

Conclusion: Opportunity and Investment

Information is at the core of public health, as it can lead to better decision-making in the prevention and control of diseases. Although EO images are widely available, there is further investment required to produce results or spatial information timely, repeatedly and accurately. In Canada, the public health sector is starting to utilize and exploit EO images in a more systematic way. Research and development of tele-epidemiology requires expert training, education, and knowledge transfer from science to operations. In addition, the enhanced development of risk-assessment models and the early warning of infectious diseases by tele-epidemiology could have an impact on current surveillance methods, intervention and controls and will call for adoption of this new approach.

Global and environmental changes challenge our understanding of the inherent mechanisms of zoonotic disease transmission. A better understanding of ecosystems and their health is needed. The EO images can help monitor terrestrial ecosystems, land use, and its changes in order to prevent and potentially help in the control of health risks over a large area in a timely manner. The EO images offer the opportunity to gather essential information on environmental determinants of health, from coast-to-coast including the Canadian Northern region and other remote communities. Several new EO satellite missions will be launched in the coming years. Satellite systems like the RADARSAT Constellation, the European Sentinels, SMAP, and other future sources of information will increase the benefits for the health sector.

CSA’s EO applications programs have focused on user needs and helped facilitate the implementation of tele-epidemiology activities at PHAC, fitting well within a One Health approach promoted internationally. In a world where satellite-based EO play a key role in the stewardship of land, ocean and atmospheric features, it could do the same by helping to manage emerging public health issues at the interface between humans, animals and the environment.

References

1. Taylor, L.H., S.M. Latham, and M.E.J. Woolhouse, Risk factors for human disease emergence. Philosophical Transactions of the Royal Society of London – Series, 2001. 356(1411): p. Biological Sciences. 356(1411):983-989.
2. World Health Organization, The control of neglected zoonotic diseases http://www.who.int/zoonoses/control_neglected_zoonoses/en/
3. OHI. One Health Initiative. 2014 January 2014]; Available from: http://onehealthinitiative.com/index.php.
3. AVMA, One Health: a New Professional Imperative, in 2008, American Veterinary Medical Association: Schaumburg, IL, USA. p. 76 pages.
4. Rogers, D.J. and S.E. Randolph, Studying the global distribution of infectious diseases using GIS and RS [Review]. Nature Reviews Microbiology, 2003. 1(3): p. 231-237.
5. Kalluri, S., et al., Surveillance of arthropod vector-borne infectious diseases using remote sensing techniques: A review – art. no. e116 [Review]. PLoS Pathogens, 2007. 3(10): p. 1361-1371.
6. Marechal, F., et al., Satellite imaging and vector-borne diseases: the approach of the French National Space Agency (CNES). Geospatial health, 2008. 3(1): p. 1-5.
7. Ogden, N.H., et al., Investigation of ground level and remote-sensed data for habitat classification and prediction of survival of Ixodes scapularis in habitats of southeastern Canada. Journal of Medical Entomology, 2006. 43(2): p. 403-414.
8. Kotchi, S.O., et al., Assessing and Monitoring Microbiological Quality of Surface Waters Using Tele-Epidemiology. Human Evolution/ Global Bioethics, 2012. 27(1-3): p. 59-64.
9. GEO, Health: Strategic Targets. 2013. http://www.earthobservations.org/geoss_he_tar.shtml
10. Turgeon, P., et al., Assessing and monitoring agroenvironmental determinants of recreational freshwater quality using remote sensing. Water Science and Technology 2013. 67(7): p. 1503-15011.
11. PHAC, Risk Assessment of Microbial Contamination of Recreational Waters in Canada Suing Satellite Imagery: Pilot Project on Public Beaches in Southern Quebec, 2013, Public Health Agency of Canada. p. 12 pages.
12. Canadian Space Agency / Aerde Environmental Research. Tele-epidemiology. 2014. p. 4.

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