Matt Toles

Polio Eradication Elution Device Design


Polio is transmitted by virus through the fecal-oral route. Though paralysis is the best known symptom of poliomyelitis, over 99% of polio infections actually do not present paralysis. As a result, identifying polio outbreaks in endemic or recently endemic regions can be challenging.

At the time, the best method for surveilling polio in the wild was to collect 500ml wastewater samples from suspect areas and transport them back to laboratories for viral analysis. This process is labor intensive due to the large volume of water necessary to transport across difficult terrain (e.g. northern Pakistan) and suffers from low recall due to the small sample volume.


I led the Engineers Without Borders team that joined Dr. Scott Meshke's EOHM Lab at the University of Washington with help from PATH and the Gates Foundation to improve on an existing prototype elution device. Rather than transport water samples out of the field, another team developed a device to filter an order of magnitude more wastewater through an electrostatic filter, trapping viruses in a container the size of a Big Mac. These filters could be easily and safely transported back to the lab for analysis, but the virus must be removed from the filters first.

We designed a device that injected beef extract into the filter housing without the need for filter removal which poses a health risk to technicians by aerosolizing the virus. The beef extract acts as a viral medium and pH buffer. After resting for a period of time, the beef extract is then removed from the housing by the same device and injected safely into a storage bottle.

Demonstrating the use of an early version of our elution device

Design and deployment of this device was challenging due to usage constrains. Firstly, the device had to be fully autoclavable, dramatically limiting material and manufacturing process choices. Secondly, the device could not use any electricity since the device was to be deployed in multiple low-resource countries where plug and voltages may not match, and replacement parts would be scarce. Finally, the device had to be simple, intuitive, and safe to use due to the risk of infection should a tube, valve, or container fail.


Our team succeeded in developing several versions of the device over the course of two years. Our elution devices were deployed for field use to labs in Pakistan, Haiti, Mexico, and South Africa. Devices performed as expected with no need for replacement or redesign. The project as a whole has outperformed existing methods in the detection of poliovirus. Development in the US and abroad is ongoing.

You can read the paper I published here.

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