A low-cost paper diagnostic test may help reduce the spread of Zika virus, with the potential of halting viral transmission in the field within two to three hours.
Specifically, scientists were able to develop a fast diagnostic strategy that can identify the particular strain of Zika virus. This supports the overall goal of using such diagnostic test in the field to test bodily samples including urine, blood or saliva.
Getting Inspiration From Ebola
In October 2014, corresponding author James Collins from Harvard University and colleagues created a technique for implanting synthetic gene systems on handy, small discs of ordinary paper. These gene networks could be used as sensor or diagnostic means that can be programmed.
For this project, they presented a color-changing technology that could detect Ebola virus by embedding a sensor to screen for particular RNA sequences, which can represent the presence of Ebola and other viruses such as Zika and measles.
The main problem encountered by this work is that the concentrations of the virus were significantly low.
In the new study, however, the researchers used blood samples of monkeys with Zika virus and Zika-infected laboratory cells. The team was able to come up with a generation approach that surpasses the primary problem of the 2014 research.
Paper-Based Diagnostic For Zika
The new process involves three procedures. The first one is to strengthen the sample RNA using a combination of enzymes and so-called "primers."
The second step is to determine the presence of Zika virus in the sample. A drop of the boosted RNA to the paper discs - which are freeze-dried and contain different cells and proteins - will change color to signify a positive Zika virus. The result may be visible to the naked eye, but a special reader may also be used to obtain more rapid findings and someday measure the viral load in the sample.
Lastly, the procedure involves CRISPR-Cas9 technology, which is a gene-editing technique that uses the immune systems of bacteria to look for genetic markers. This technique comes next after Zika detection and has a primary goal of differentiating between strains efficiently, even if they differ by only one nucleotide.
"We have tested our diagnostic systems against closely-related strains of the Dengue virus and found that within the first two steps, our system can readily distinguish Zika from Dengue," says co-first author of the study Alexander Green.
Green says that the third step just improves the accuracy of the Zika detection. As they embark on the translation of this technique, they plan to verify it against numerous clinical specimens.
Co-first author Leslie Dan says all the recent news about Zika has been heartbreaking and that the team is hoping that a tool like this can help tone down the effects of the outbreak until a vaccine can be invented.
Zika Detector On The Go
All the materials needed to perform this low-cost paper diagnostic test can be freeze-dried and transported in the field and therefore can be used for pandemics.
The technology can be tailored to detect different pathogens and is very convenient given that it is paper-based. It is also more potent and can quickly respond to create new diagnostics while an outbreak is ongoing.
Currently, the team is seeking private and public deals to help them commercialize their technology to make it available for the entire globe.
The Deadly Zika Virus
Zika virus infection is a life-threatening condition that can afflict pregnant women, babies, and the general population.
The virus was once known to be a self-limiting disease that is characterized by fever, rashes and chills that go away with conservative therapy. However, as the outbreak continues around the world, more and more medical conditions are being linked with Zika. Recently, the Centers for Disease Control and Prevention confirmed that Zika virus is indeed the reason for microcephaly and other birth defects among babies born to Zika-infected mothers.
The study was published in the journal Cell on May 6.