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DigitalGlobe’s Satellite Imagery for Polio Eradication

(By Rhiannan Price – September 9, 2016)

The recent polio outbreak in Borno, Nigeria, is a reminder that gaps in surveillance systems have prompted a whole array of health challenges.

After more than two years without new cases of polio, two children in Borno state, Nigeria have been paralyzed by the disease, a setback for global eradication.

While large-scale immunization campaigns have helped the Africa continent realize nearly two years free of any new cases, many children in northern Nigerian were simply out of reach. The presence of Boko Haram has weakened the health surveillance system, and persistent conflict means that these children are difficult to find, difficult to reach, and thus difficult to immunize. The World Health Organization (WHO) estimates that more than half of the health facilities in Borno State are not functioning, and of the two new polio cases, one of the children still cannot be reached because of the security issues.

With the ongoing instability, there are thousands of displaced persons throughout the Lake Chad region, making the risk of transmission extremely high. Reaching these children requires vaccinating populations as they move in and out of inaccessible areas and using local-level groups and organizations, such as religious institutions and community based organizations, to negotiate access for vaccination teams. In addition to the migration issues, it is currently the peak of the rainy season in Borno and major floods are expected in the coming weeks. Health workers will need military escorts over long distances on rough terrain and may not be able to reach every community.

This recent polio outbreak is a reminder that these health interventions do not exist in a vacuum. Protracted conflict greatly exacerbates these types of global health crises. In 2013, DigitalGlobe helped put northern Nigerian communities on the map; however, because of Boko Haram, in a matter of just three years, those maps have become outdated, making health surveillance much more difficult. Gaps in surveillance systems have prompted a whole array of health challenges, and, according to WHO, estimated mortality rates in the area are four times higher than emergency thresholds.

To support current immunization campaigns, DigitalGlobe is working with the Global Polio Eradication Initiative to update the maps in Borno. With DigitalGlobe’s high resolution imagery, individual settlements are easy to identify, and leveraging satellite imagery means we have a lens to even the most insecure areas of the world, places that are off limits even to health workers.

While these communities are easily identified in imagery, extracting information over such a large area on short timelines requires a scalable methodology. To enable a quick turnaround, DigitalGlobe uses advanced machine learning-based algorithms to evaluate terabytes of imagery and identify possible human settlements. To ensure the most accurate results possible, DigitalGlobe turns to volunteers in a public crowdsourcing campaign to verify findings. Using Tomnod, volunteers worldwide confirm whether or not an image contained a settlement. In 2013, more than 45,000 volunteers helped validate the village detection results across Nigeria, Somalia, and Pakistan. For Somalia, the volunteer-driven campaign lasted three days and covered over 120,000 polygons. The end result was a map of 285,103 settlements that otherwise might not have been reached.

When polio appeared in the Middle East in 2013, the emergency vaccination campaigns reached more than 25 million children and contained the outbreak within a matter of months. Polio also returned to Somalia in 2013 and the rapid regional immunization campaigns were able to stem further transmission.

Eyes on the goal

The same mapping exercise is happening again in Nigeria. That way, health workers have the best information possible as they lead immunization efforts in recently unchartered territory.

Despite this recent setback, the world is still very close to reaching the goal of polio eradication. Since 2000, more than 10 billion doses of oral polio vaccines have been administered to nearly 3 billion children worldwide. As a result, more than 13 million cases of polio have been prevented, and the disease has been reduced by more than 99%.

Only 21 wild polio cases have been reported so far in 2016, compared to 34 cases at the same point last year. And these cases are contained to Pakistan and Afghanistan, which are eerily similar, conflict-ridden environments like Borno.

Big Data analytics, in conjunction with innovative approaches like crowdsourcing, offer promising inputs to addressing information gaps. That said, locating these communities is just the beginning. Establishing a comprehensive plan to achieve universal health coverage and ensure access to necessary medicines and vaccines is the challenge ahead. Innovative technologies have a crucial role to play to realize this vision, and in partnership with the international community, eradicating polio and improving our health systems overall is entirely possible.

Rhiannan Price
Senior Manager
Seeing a Better World Program at DigitalGlobe