October 28, 2021

I, Science

The science magazine of Imperial College

Location data from mobile phone users in Namibia might help control the spread of malaria ...


Namibia aims to eradicate malaria by 2020. The country has already reduced its yearly burden of malaria cases from over 610,000 in 2004 to 14,400 in 2011. Now, as malaria retreats into hard-to-reach recesses of the country, the Namibia National Vector Borne Diseases Control Programme (NVDCP) is turning to mobile phone data to map population movements and help target its elimination campaign more effectively.

Understanding population movements is crucial for malaria elimination efforts. People drifting back from infected areas into treated areas can quickly undo any progress made, as seen in Haiti in the 1960s. Human movements in developing countries, however, are difficult to track. Travel history surveys and census data are a blunt instrument and often lag behind what is actually happening on the ground. Mobile phone call data may provide a way to quickly and accurately map population movements within a country and better understand how diseases like malaria are being spread.

The NVDCP worked together with the University of Southampton to create a detailed malaria ‘risk map’ for Namibia based on diagnosed cases and environmental data. The team then combined this with the anonymised mobile phone call records of over a million people in order to identify transmission ‘hotspots’ where areas of high people movement and malaria risk coincided. These ‘hotspots’ can now be targeted by malaria elimination attempts such as deployment of bed nets, pesticides and drugs.

Lead researcher Dr Andrew Tatem from the University of Southampton says: “We’re talking with [the NVDCP], we’re working out how we can best help them use [the mobile phone data] in terms of which health facilities should be collaborating together, the kind of community maps that we produced in the paper and also working with the phone company who’s continuing to supply more data so that we can have an updated picture on how things are changing.”

Using mobile phone data, however, is not without its drawbacks. Mobile phone companies have to be reassured that use of their data will not breach customers’ privacy. Dr Tatem explains: “It’s very difficult data to obtain. There had to be [signed] agreements in place that only anonymised data and aggregated data would be used so that we couldn’t identify individuals.”

The reliability of the data also needs to be established says Dr Hugh Sturrock of the Global Health Group at the University of California, San Francisco: “It will be really important to try and validate these methods to make sure they are giving us reliable data. One issue is that not everyone has a mobile phone, not everyone makes regular calls or texts to allow you to understand movement patterns and multiple people might use one phone. Getting a better understanding of this issue will allow us to correct for any bias.”

Both Dr Tatem and Dr Sturrock agree that malaria elimination is achievable for Namibia but success also depends on the efforts of neighbouring countries. Dr Sturrock says that malaria elimination in Namibia,“will involve working with neighbouring countries to stop importation of parasites, mapping cases back to village or even household to allow interventions to be highly targeted and encouraging high rates of screening and treating to stop as many infections as possible. Additionally, the malaria control program will need to sustain funding to ensure that surveillance is extremely good. From past experience we know that if funding dries up, malaria comes back.”

So regardless of these innovative techniques, malaria elimination in Namibia still relies on the basic foundations of any disease eradication programme in that it needs international co-operation and sufficient funding. This is why organisations like the Global Health Group are so important and why malaria elimination should continue to be a global priority and not just an issue for those countries affected.


IMAGE: Muhammad Mahdi Karim