Now that scientists have determined an official causal link between Zika virus and the birth defect microcephaly as well as warned that the outbreak is just beginning, researchers have been rushing to come up with ways to quickly diagnose the virus.
Diagnosing Zika has been tricky because the symptoms are very similar to other insect-spread viruses like dengue and chikungunya. Testing for the virus is a long process because blood samples have to be tested for either Zika antibodies, which the test can't distinguish from dengue antibodies, or evidence of pieces of the viral genome and those tests can take weeks.
In places where dengue and Zika are both present, testing can remain inconclusive, and in the case of pregnant women, there's been a pressing need to get it right so they can receive necessary screening and support.MIT researchers, along with experts at the Wyss Institute at Harvard, have developed a testing kit that can not only distinguish Zika from dengue, but it can produce results in just a few hours. To top it off, the paper-based test is inexpensive and compact so that it can be easily deployed in the regions where its most needed.
The device is based on a paper test the same team developed for diagnosing Ebola. Small paper disks are embedded with sensors that can detect 24 different RNA sequences found in the Zika viral genome. If the sensors pick up any of those sequences, a series of interactions turn the paper from yellow to purple. An electronic reader helps to read the changes, especially if multiple RNA sequences are detected.
The researchers also developed a step that boosts the viral RNA in a blood sample and makes the test a million times more sensitive.
The team tested the device for accuracy using synthetic Zika RNA added to human blood serum as well as using blood samples from monkeys that were infected with the virus and the test was able to detect Zika at very low concentrations in both instances and also distinguish it from dengue samples.
“Here we’ve done a nice proof-of-principle demonstration, but more work and additional testing would be needed to ensure safety and efficacy before actual deployment,” said James Collins, the Termeer Professor of Medical Engineering and Science in MIT’s Department of Biological Engineering and Institute for Medical Engineering and Science (IMES) and the leader of the research team. “We’re not far off.”
The team is now working with other scientists to further develop the technology and get it ready for deployment.