I spy an outbreak: the scientists who track diseases from space

What do you see when you look up at the night sky? A few constellations, the North Star, or maybe the moon. We tend to think about space from our perspective on the ground, but what about looking down from space to earth? This is the perspective through which a special team of researchers at the Public Health Agency of Canada (PHAC) study our world, using space technology to track diseases.

A unique approach to investigating infectious disease

Stéphanie Brazeau leads the geomatics team at PHAC's National Microbiology Laboratory (NML) in St. Hyacinthe, Quebec. The team is taking a unique approach to investigating infectious diseases, such as Lyme disease, West Nile virus and COVID-19 using data gathered from satellite Earth observation or geographic data. Over the past decade, they have collaborated with the Canadian Space Agency (CSA) to advance the application of space technologies and geospatial data in public health. This has blossomed into a successful partnership, and recently PHAC and the CSA co-led the development of a book on the topic, Earth Observation, Public Health and One Health.

The book, co-edited by Ms. Brazeau and Dr. Nicholas Ogden, Director, Public Health Risk Sciences, is about how scientists use satellite imagery to study and monitor the environment, climate and social factors that can explain where and when infectious and chronic diseases occur. The book can be accessed free online here (English only). The “One Health” part of the book’s title refers to the practice of bringing together experts from human, animal and environmental health to support evidence-based public health actions, since these areas are all interconnected. The book, containing contributions from 30 international co-authors, is an example of this idea in action.

What is geomatics?

Essentially, geomatics involves the collection and analysis of geographic data – which includes environmental data like vegetation, climatic data like temperature, and data on disease cases. Each factor intersects to paint a picture of which locations are at risk for infectious diseases.

“Of course, we do not see diseases like West Nile virus in our satellite images,” says Ms. Brazeau. “We look for signs that indicate the disease might appear or move into an area. Different conditions favour different diseases. West Nile may spread with changing temperatures and soil moisture, and then we can tell that the mosquitos transmitting the disease may be present in areas detected from the satellite data.”

The team uses special images taken from satellites to find these at-risk locations. “By combining information on habitat and climatic conditions, the geomatics team can create risk maps for various infectious diseases. We use these maps to help public health professionals conduct their work,” says Ms. Brazeau.

This information helps identify where to increase monitoring for infectious diseases, who is at risk, and helps governments make decisions to prevent further spread of infections.

A recent example of this work in action can be found in the geomatics team’s maps and dashboards that provide insight about the the COVID-19 pandemic at the regional health level, including identifying hot spots for infection. By identifying the number of COVID-19 cases per 100,000 people and comparing it to the doses of vaccines administered, it is possible to obtain a map that allows us to assess the impact of vaccination on the infection rate.

Supporting public health response

The information received from satellite Earth Observation and geographic data help scientists detect changes and conditions that may be favorable for an epidemic. They can support the public health response to an outbreak by locating at-risk and vulnerable populations. The resulting maps help to target public health intervention to the highest risk areas.

Through their capabilities, Earth Observation Satellites and geographic data have completely revolutionized and modernized the way we study infectious diseases. The geomatics team can work to assess remote areas of the country from within the NML more accurately, more fully and more in depth than ever before.