New Zika Test Delivers Results in a ‘New York-Minute’

Zika Virus-Specific Diagnostic test produces results in minutes, not hours

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Researchers are developing a novel test for Zika virus that uses saliva to identify diagnostic markers faster than the current commercial tests.

The new Zika test has the potential to produce results in a matter of minutes instead of hours or days.

Current RT-PCR tests take around three hours and specific antibody tests can take several weeks.

This test, which was adapted from an existing model developed by New York University (NYU) and Rheonix for rapid HIV test can detect both viral RNA and antibodies.

“When we developed the HIV test, we knew we could use the same model for any infectious disease. All we need to know is the nucleic acid sequence and an antigen to identify specific antibodies,” Malamud said.

This rapid Zika test combines both nucleic acid and antibody assays using saliva, given that Zika virus and antibodies persist in saliva. A saliva test is noninvasive, cost-effective, and easier to collect than blood or urine.

NYU researchers are using a method called isothermal amplification, which can detect a virus’ nucleic acids in as little as 20 minutes, and antibody tests that can take less than an hour using Zika-specific antigens.

“The sooner you can identify a pathogen, the sooner steps can be taken to treat and isolate people,” said study author Daniel Malamud, Ph.D., professor of basic science at NYU Dentistry.

Zika diagnosis is a challenge because it shares vectors, geographic distribution and symptoms with Dengue virus and Chikungunya infection, and the three illnesses are often misdiagnosed.

Given the risk of adverse pregnancy outcomes in women infected with Zika during pregnancy, it is particularly important to distinguish between the 3 viruses.

Currently, blood samples are most often used to test for Zika virus and are typically processed using a common diagnostic technique called real-time polymerase chain reaction (RT-PCR).

But blood may not be the best fluid: while the virus disappears in the blood a week or two after a person is infected, it can persist longer in saliva, semen, and urine. In addition, antibodies can remain for months or years in those bodily fluids, which is why it is essential for diagnosis to also detect antibodies after infection.

As described in PLOS ONE, after showing this new test could confirm the presence of the virus using both purified Zika RNA and Zika-infected saliva, they adapted the test to the Rheonix CARD® cartridge and workstation, enabling them to estimate the viral load in saliva samples.

Knowing the amount of virus present is useful for understanding disease severity and immune responses, particularly among pregnant women and fetuses.

The researchers also identified Zika-specific antigens – which can be used to detect the Zika specific antibodies needed for testing – using a high-density peptide microarray they describe in JoVE.

Researchers at NYU and around the world are continuing to validate their findings in further experiments using Zika-infected saliva.

This study did not identify the proposed test pricing, nor did it discuss the commercial availability of the test.

In addition to Sabalza, Malamud, and Montagna, study authors on the PLOS ONE article include Cheryl A. Barber, Talita Castro, and William R. Abrams of NYU Dentistry and Rubina Yasmin, Beum Jun Kim, and Hui Zhu of Rheonix, Inc. Barber and Abrams of NYU co-authored the JoVE article.

Competing interests: We have the following interests: R.M., R.Y., B.J.K., and H.Z. are employed by Rheonix, Inc. In addition, each own shares and/or options to purchase shares in Rheonix, Inc.

The research was supported by the National Institute of Dental and Craniofacial Research (NIDCR) of the National Institutes of Health (R44DE024456 and 3R44DE024456-03S1). Support was also provided by a Small Business Innovation Research administrative supplement grant from NIDCR R44 DE024456 that evolved out of NIDCR grant U01 DE017855 for the development of a confirmatory point-of-care diagnostic for HIV.

About NYU College of Dentistry:  Founded in 1865, NYU Dentistry is the third oldest and the largest dental school in the US, educating nearly 10 percent of all dentists. NYU Dentistry has a significant global reach with a highly diverse student body. Visit http://dental.nyu.edu for more.