A global priority
Infectious diseases bring devastation to the poorest and most vulnerable communities in the world. Caught in a cycle of disease and poverty, children are unable to go to school and adults are unable to work, leading to reduced economic development. Reducing the impact of these diseases is a global priority and many agencies are working together on ambitious programs to eliminate many of them during the next decade.
If we are to eliminate any of these diseases, then surveillance is critical. We need to be monitoring hot-spots of re-emergence but we also need to screen communities to identify carriers of infection - people who appear healthy but have the potential to infect others. Furthermore, the tests should be low-cost and user-friendly - enabling health workers to test entire communities that are at risk.
With funding from EPSRC we have been developing our first generation of tests in a paper-based format, enabling us to determine the species causing the infectious disease, from a finger-prick of blood. This information can be extremely important as it can inform the treatment of the patient. Paper tests are not only low cost but they are easily disposed of by burning. Perhaps most importantly, we have employed very accessible production techniques; using commercially available hot-wax printing to develop a device that is cheap and easy to produce in countries where the disease elimination initiatives are taking place.
After initial development in the UK, we tested our devices in the Mayuge District, on the banks of Lake Victoria, working with healthcare workers from Uganda's Ministry of Health. The design of the device means that testing can be done by a non-expert - using folding of the paper in a manner similar to origami to process the sample. Importantly, we integrated the sample preparation into a lateral flow device - akin to a conventional pregnancy test - so that untrained staff could easily read the result - with the appearance of coloured lines indicating the outcome.
The study enabled us to take a successfully lab-proven malaria test and explore its deployment into a rural population, in a low-resource setting. As a preliminary study, we were also greatly encouraged by results that were 98% accurate, which compared very favourably with the more traditional immunodiagnostics (82%) and microscopy (86%).
The studies have also taught us about future innovations that are needed, not only to improve performance and assay robustness, but also to mitigate against cross-contamination, when doing multiple tests in the same village, over many days. We have ideas on how to better interface the sample with the device and how to increase the speed of the results.
We have also now explored the concept of "multiplexed" testing malaria alongside schistosomiasis, as a sentinel test. This device particularly excited both the healthcare workers from the Ministry of Health, who see great potential for this test to improve treatment and save time and resources.
We are now planning collaborations with non-governmental organisations (NGOs), social scientists and community based organisations to further develop the test, assess its economic impact, and find ways to implement the device for use in disease control interventions.
Using our origami tests, we have now worked both in Africa and India and explored the potential of multiplexed 'sample-to-answer' origami tests for infections caused by trematodes, protozoa, bacteria and viruses, from a variety of samples including blood, sperm and faeces in both humans and animals. The recent involvement of a healthcare technology assessment team to demonstrate the both the health and economic benefits of potential interventions is an important future development.