Zeroing in on Zika
Latin America and Canadian scientists are working on a portable diagnostic technology that could be a game-changer in the battle against diseases such as Zika
Posted by Brian Banks on July 25, 2018
Zika. Dengue. Yellow Fever. Chikungunya.
In the developed world, these mosquito-borne infections are the stuff of fearful headlines, graphic images and stories of outbreaks in far-away lands.
But in rural and low-income areas of Latin America, where these pathogens are endemic, they’re a clear and present danger.
Yet the viruses’ presence in these regions is only part of the problem. Compounding the threat is the fact that diseases such as Zika and dengue are hard to isolate and tell apart without sophisticated testing in labs located in just a handful of large urban centres. That leads to long delays between disease outbreaks and their diagnosis and treatment.
“You want to be able to contain an outbreak as soon as you can,” says Keith Pardee, Canada Research Chair in synthetic biology and human health and an assistant professor at the Leslie Dan Faculty of Pharmacy at the University of Toronto. “But right now, when someone has symptoms of infection, those samples are put on ice and transported to larger centres. In outbreaks, that infrastructure can be overwhelmed or basically just isn’t in the right place.”
Pardee’s solution? He’s leading the development of a portable diagnostic technology that can distinguish different diseases — and different strains of those diseases — as accurately as the current laboratory gold standard, yet is easily deployed to the site of an outbreak, requires no sophisticated equipment or technical knowhow to run and yields results in hours, not days or weeks.
His team is now midway through a three-year project jointly funded by the International Development Research Centre and Canadian Institutes of Health Research to refine the technology and begin field-testing and trials with three national research labs in Brazil, Ecuador and Colombia. This project is focused specifically on Zika but Pardee says the technology can be easily adapted to target dengue, Chikungunya, yellow fever, Ebola or even HIV.
The science of synthetic biology underlying this work is cutting edge, involving CRISPR gene editing and programmable gene circuit-based sensors extracted from cells and freeze-dried for non-refrigerated transport. But the application is incredibly simple. A nurse or doctor merely has to take a prick of blood or a urine sample from a patient, put a drop on a microchip cartridge and insert it in a small, portable machine. Within hours, a paper readout changes colour — think litmus paper or a pregnancy test — to indicate the presence or absence of the virus.
“In Brazil, few Zika cases are laboratory-confirmed because the lack of resources and the fact current diagnostic technology is expensive and requires special equipment,” says Lindomar Peña, a principal investigator in the virology department at the Oswaldo Cruz Foundation in Rio de Janeiro, one of Pardee’s partners in Latin America.
Peña’s lab was one of the first to detect Zika in Brazil in 2016 and report its related neurological and developmental defects. He says he is “thrilled” to be working with Pardee and his peers at Ecuador’s National Institute of Public Health Research and El Bosque University in Colombia, calling it “a great opportunity” to overcome their current diagnostic limitations.
The first phase of their joint work, which is expected to be running at full capacity in August, is focused on comparing the accuracy of Pardee’s technology with the gold-standard diagnostic process on patient samples gathered in affected areas. Samples are processed using small portable computers built by two research assistants in Pardee’s lab. That data is then uploaded to the cloud so Pardee can compile and analyze it. A low-end industrial version of the same computer would cost at least $15,000, says Pardee, but “we built ours for $300 to $350.”
The project’s second field phase, slated to start in January, will see the portable devices taken out of the labs and into the countryside. “This box, if you put a battery on it, can run for nine hours,” says Pardee. “So you could literally have it in your car and do this anywhere.”
By the time the project ends, Pardee hopes to have screened 3,000 patient samples in the lab and done 100 to 200 tests in the field. “For it to become a certified diagnostic technology there’s still quite a bit of work to do,” he says. “But we’re on the road to that.”
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This is part of an ongoing series of stories on international development projects supported by Canada’s International Development Research Centre, presented in partnership with Canadian Geographic. The stories appear online once a month at idrc.canadiangeographic.ca.
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