Major new funding, testing sought as disease rages

By Gary Tufel

One of the biggest healthcare surprises of the past year has been the sudden and frightening rise to prominence of the Zika virus in the Western Hemisphere. An arbovirus spread predominantly by the Aedes aegypti mosquito, Zika typically causes a mild illness whose symptoms include conjunctivitis, fever, joint pain, and rash lasting several days to a week.

Previously thought to be a mild virus that resulted in symptoms for only about 20% of those infected, Zika is turning out to be the cause of a number of serious diseases. Of special concern is recent definitive evidence that the virus causes microcephaly in infants as well as causing serious brain and nerve cell damage.

And now, as the Northern Hemisphere enters the warm spring and summer mosquito-breeding seasons, healthcare professionals are expressing concern that the risks associated with the Zika virus are still being underestimated, and that its pandemic status in other parts of the world might be replicated in North America.

With the recent and rapid spread of the Zika virus in the Western Hemisphere, laboratory testing has become even more important. According to the US Centers for Disease Control and Prevention (CDC), lab testing should be considered for patients with acute arthralgia, fever, myalgia, or rash who are living in or have traveled within the previous 2 weeks to an area with ongoing transmission.1

But it seems there may be still more surprises associated with Zika. Now, researchers are even questioning whether mosquitoes are the primary cause of the virus’s transmission. In a recent study, researchers at the University of California, Los Angeles (UCLA), reviewed the genetic sequences of Zika virus specimens from several decades, and found that the virus has undergone significant changes over time. The virus’s ability to mutate, the researchers suggest, is a reason why it is able to trigger different types of disease.

The UCLA researchers also noted that the sequenced strains of Zika from mosquitoes do not match all the strains in humans from the current outbreak, suggesting that more people than expected may be getting the virus some other way. Cases of sexual transmission may play a larger role than previously thought, leading CDC to recommend that people in areas of active Zika transmission should practice safe sex, and even abstain during pregnancy.2,3

This article looks at some of the milestone discoveries about Zika from the past year, and how clinical laboratories and in vitro diagnostic manufacturers are working to improve the tools available to track and diagnose the virus.


Margaret Chan, MD, MPH, World Health Organization.

Margaret Chan, MD, MPH, World Health Organization.

In late January, Margaret Chan, MD, MPH, director general of the World Health Organization (WHO), said that the spread of the Zika virus had gone from a mild threat to one of alarming proportions. In response, she convened an emergency meeting of the organization’s international health regulations committee, to gather advice on the severity of the health threat associated with the continuing spread of the Zika virus.

Setting the tone for the meeting, Marcos Espinal, MD, DrPH, MPH, director of communicable diseases and health analysis at the Pan American Health Organization, noted that spread of the mosquito-borne disease is likely to affect many more people before it can be halted. Without suggesting a timeframe, he commented that “we can expect 3 million to 4 million cases of Zika virus disease.”4

Marcos Espinal, MD, DrPH, MPH, Pan American Health Organization.

Marcos Espinal, MD, DrPH, MPH, Pan American Health Organization.

After reviewing the evidence available on February 1, the WHO committee issued a statement declaring the recent cluster of microcephaly cases and other neurological disorders reported in Brazil “a public health emergency of international concern.”5

“A coordinated international response is needed to improve surveillance, the detection of infections, congenital malformations, and neurological complications; to intensify the control of mosquito populations; and to expedite the development of diagnostic tests and vaccines to protect people at risk, especially during pregnancy,” the committee concluded.


In January, CDC put its command center at the highest level of alert, a measure reflecting growing concern about the prospect of the Zika virus gaining a foothold in the mainland United States.

Zika is not entirely unknown to the United States. In 2007, when the mosquito-borne disease had its first large outbreak in the Pacific island nation of Micronesia, the virus directly touched the United States, sickening one American traveler.6 But locally transmitted cases of Zika virus were unknown in the Western Hemisphere until 2015, when reports of Zika infection suddenly sprang up in Brazil and rapidly spread to nearly 30 countries in Central and South America and the Caribbean.

Anthony S. Fauci, MD, National Institute of Allergy and Infectious Diseases.

Anthony S. Fauci, MD, National Institute of Allergy and Infectious Diseases.

In a March White House press conference, Thomas R. Frieden, MD, MPH, director of CDC, and Anthony S. Fauci, MD, director of the National Institute of Allergy and Infectious Diseases (NIAID), offered an overview of recent findings about the Zika virus, with little good news in the mix:

  • Zika causes worse birth defects than anyone suspected, potentially including some that won’t be confirmed for many years.
  • Zika almost certainly causes a paralyzing condition called Guillain-Barré syndrome.
  • The virus is expected to infect several million people.
  • The Aedes aegypti mosquitoes that serve as vectors for the Zika virus may be resistant to some of the pesticides used to fight them.
  • It isn’t known how common the Aedes aegypti mosquito is in the United States, or where they are located.
  • A vaccine against the Zika virus is more than a year away.

In April, CDC officials updated reporters with recent analyses about the spread and effects of the Zika virus. New information indicates that the potential geographic range of the mosquitoes transmitting the virus reaches farther northward than originally believed, with the Aedes aegypti species present in all or part of 30 states, not just 12. And CDC researchers also revealed that Zika infection can be spread sexually, leading the agency to update its guidance to couples.7

Anne Schuchat, MD, Centers for Disease Control and Prevention.

Anne Schuchat, MD, Centers for Disease Control and Prevention.

“Most of what we’ve learned is not reassuring,” said Anne Schuchat, MD, CDC’s principal deputy director. “Everything we know about this virus seems to be scarier than we initially thought.”8

Most notably, the CDC update confirmed earlier suspicion that the virus causes birth defects. “There is no longer any doubt that Zika causes microcephaly,” said Frieden. The conclusion was reached after evaluating “mounting evidence from many studies,” and signifies “an unprecedented association” in medicine, he said.

Top Zika investigators now believe that the birth defect microcephaly and the paralyzing Guillain-Barré syndrome may be just the most obvious maladies caused by the virus. Fueling that suspicion are recent discoveries of serious brain and spinal cord infections—including encephalitis, meningitis, and myelitis—in people exposed to Zika.

Schuchat noted that CDC analyses also linked infection with the Zika virus throughout a longer period of pregnancy to a broader array of birth defects, including premature birth and blindness.

And scientists also recently released two other studies: one showing the virus seems to home in on and kill developing brain cells, and one showing it may cause rare nerve damage that resembles multiple sclerosis.9


Is it merely a coincidence that the global health emergency involving the rapid spread of Zika virus in the Western Hemisphere took root in 2015, the hottest year in the historical record?

Scientists say it will take years to figure that out. But one recent report points to the possibility of causative links between global warming, the heat-loving Aedes aegypti mosquitoes that transmit many arboviruses, and the rise of the current global Zika health emergency.8

Experts admit that other factors may have played a larger role in starting the current Zika crisis. But they also point to the parallel spread of the dengue virus, the cause of dengue fever, which sickens 100 million people and kills thousands every year. Far from being mere coincidents, say the experts, these trends should be interpreted as warnings.

Over the coming decades, global warming is likely to increase the range and speed up the life cycle of the Aedes mosquitoes that serve as vectors for Zika and other arboviruses, encouraging their spread deeper into temperate countries such as the United States.

Recent research suggests that under a worst-case scenario involving continued high global carbon emissions coupled with fast population growth, the number of people resident in regions with exposure to the Aedes mosquito could more than double, from roughly 4 billion today to as many as 9 billion by the end of this century.10


Thomas Frieden, MD, MPH, CDC.

At CDC’s April press conference, CDC Director Frieden reported on a recent visit to Puerto Rico, the US territory that he calls “ground zero” for Zika in the United States. His comments highlighted the complexity of fighting the Zika virus. For instance, an effort to install screens in homes to keep mosquitoes out will be tricky, he said, because many homes have open eaves, which are harder to screen than windows.

And mosquitoes in parts of Puerto Rico have developed resistance to some of the insecticides most commonly used to fight them. “We are finding widespread resistance to some insecticides,” Frieden told reporters.11

At the end of April, Secretary of Health and Human Services (HHS) Sylvia M. Burwell announced the award of $5 million in funding to 20 health centers in Puerto Rico to further combat Zika virus disease. The centers will use the funding to expand voluntary family planning services, including contraceptive services, outreach, and education, and to hire more staff.12

Sylvia M. Burwell, Department of Health and Human Services.

Sylvia M. Burwell, Department of Health and Human Services.

“In Puerto Rico, and around the world, the Zika virus is a serious and challenging health threat,” said Burwell. “We are committed to doing everything we can to combat this threat and to help strengthen healthcare in Puerto Rico.”

Evidence that Zika’s damage may be more varied and widespread than initially believed adds pressure on affected countries to control mosquitoes and prepare to provide intensive—and, in some cases, lifelong—care to more patients. The newly suspected disorders can cause paralysis and permanent disability—a clinical outlook that adds urgency to vaccine development efforts.13

The more infectious disease specialists and public health officials learn about the Zika virus, the more frightening it looks. More money to combat the virus, they say, is urgently needed.

The situation is so dire that President Obama has asked for $1.9 billion in emergency funding, in part to expedite efforts to develop a Zika vaccine.

At their March press conference before White House reporters, CDC Director Frieden and NIAID Director Fauci pressed their case for Congress to approve the president’s request for $1.9 billion in emergency funding to fight the Zika virus, insisting the virus poses an urgent threat and begging Congress to free up money to pay for the fight. Efforts to fight other diseases, from HIV to dengue, they noted, are on hold while money is cobbled together for the anti-Zika effort.

Reflecting the escalating urgency of the situation, the president also announced the administration’s intention to divert money already earmarked for efforts to end the Ebola virus epidemic in West Africa to the fight against Zika. The White House said that in the absence of the new emergency funds requested by the president, the administration would redirect $589 million—mostly from money already provided by Congress to tackle the Ebola virus—to prepare for the emergence of the Zika virus in the continental United States as the weather warms.14


An electron microscopy representation of the surface of the Zika virus with protruding envelope glycoproteins (red). Courtesy Kuhn and Rossmann research groups, Purdue University.

Figure 1. An electron microscopy representation of the surface of the Zika virus with protruding envelope glycoproteins (red). Courtesy Kuhn and Rossmann research groups, Purdue University.

Despite the bleak outlook for near-term control of the Zika virus, there have been some breakthroughs in our understanding of Zika infections, including the success of a recent study to determine the molecular structure of the Zika virus.

A near-atomic-level map of the Zika virus shows its structure to be largely similar to those of dengue virus and other flaviviruses, but with a notable difference in one key surface protein. According to scientists funded by NIAID, the variation in Zika envelope (E) glycoproteins—180 of which are packed on the virus’s outer shell—may provide clues to better understand how Zika virus enters human cells, and suggests ways to combat the virus with drugs or vaccines aimed at the newly detailed region.

Purdue University’s Richard Kuhn, PhD (left), and Michael Rossmann, PhD, stand with the cryoelectron microscope used to determine the structure of the Zika virus. Courtesy Purdue University/Mark Simons.

Purdue University’s Richard Kuhn, PhD (left), and Michael Rossmann, PhD, stand with the cryoelectron microscope used to determine the structure of the Zika virus. Courtesy Purdue University/Mark Simons.

Working with NIAID investigator Theodore Pierson, PhD, and colleagues at Purdue University, NIAID grantees Richard Kuhn, PhD, and Michael Rossmann, PhD, created the picture of a mature Zika virus particle using a technique called cryoelectron microscropy (see Figure 1). The process involves freezing virus particles and firing a stream of high-energy electrons through the sample to create tens of thousands of two-dimensional electron micrograph images. The micrographs are then combined to yield a composite high-resolution, three-dimensional view of the virus.15


In the United States, specialized laboratory blood testing for the arthropod-borne chikungunya, dengue, and Zika viruses is performed primarily by CDC and several state and territory public health departments. While there is an FDA-cleared, commercially available kit for the diagnosis of dengue virus infection, however, no tests for the diagnosis of chikungunya or Zika virus infection have yet received FDA clearance for clinical lab use.16

Mary Hayden, MD, Rush University Medical Center.

Mary Hayden, MD, Rush University Medical Center.

There are reasons that a commercial test for dengue virus exists, while equivalent assays for chikungunya and Zika are lacking, says Mary Hayden, MD, professor of medicine and pathology at Rush University Medical Center. “Dengue has been found in the Americas since the 1980s, so it isn’t a newly arrived virus,” she says. “But both chikungunya and Zika are relatively new to the Western Hemisphere. Chikungunya was first identified in the Western Hemisphere in 2013, and Zika was first identified just last year.”

In addition, says Hayden, tests for such arboviruses often encounter problems with specificity. “There is serologic crossreactivity among antibodies to the dengue, yellow fever, and Zika viruses, all of which are flaviviruses. Chikungunya is an alphavirus, and it is uncertain whether there is serologic crossreactivity between chikungunya and Zika antibodies. But antibody tests for the Zika virus often crossreact with the chikungunya and dengue viruses, so it’s hard to develop a Zika-specific test, such as an ELISA, that would be appropriate for a clinical lab.”

The lack of a commercial diagnostic suitable for clinical lab use has left the responsibility for Zika virus testing in the hands of public health authorities. “CDC screens for the Zika virus, and then confirms its results using a slow-turnaround plaque-reduction neutralization assay,” says Hayden. “The current procedures are similar to the testing situation that occurred when the West Nile virus arrived in the United States. Once West Nile virus became endemic in this country, testing began to be conducted not only by CDC and other public health labs, but also in big reference labs.”

If the incidence of Zika virus infection in the United States rises significantly during the coming summer, as many experts predict, it’s possible that clinical labs will become involved in Zika testing, says Hayden. But it’s unlikely that in vitro diagnostics manufacturers will develop commercial tests for FDA clearance unless the incidence of Zika infection increases in the United States and other Western countries, providing a financial incentive to develop tests for use in clinical labs.


Helen Lazear, PhD, University of North Carolina, Chapel Hill.

Helen Lazear, PhD, University of North Carolina, Chapel Hill.

Laboratories and IVD manufacturers that intend to develop tests for Zika virus will need to confront a number of challenges, beginning with the issues of specificity and crossreactivity that are already known to affect existing tests. “In the case of flaviviruses (including Zika virus) a major challenge is that the polyclonal immune response to one flavivirus can crossreact with other flaviviruses, making it challenging to develop highly specific serological assays,” says Helen Lazear, PhD, assistant professor of microbiology and immunology at the University of North Carolina, Chapel Hill. “This problem poses the greatest challenge in people with a history of infection by multiple flaviviruses.”

In Latin America, most people are infected with dengue virus during childhood, so a later Zika virus infection represents a secondary flavivirus infection. In turn, the antibody response to Zika virus will be dominated by a memory response from crossreactive dengue antibodies, rather than Zika-specific antibodies, explains Lazear.

When developing a test, “the challenge is to develop recombinant antigens that will react only with virus-specific antibodies,” says Lazear. “PCR-based assays are specific, but only useful during a short window of acute infection. Serological assays are essential for any diagnostics outside this window.”

Creating a test that is ready for broad use in clinical laboratories can present additional challenges. “Commercial diagnostic assays need to be robust, easy to use, and high-throughput,” says Lazear. “It is easier to develop a specific assay for laboratory use than to make one that is suitable for deployment in the field. For example, an assay that relies on measuring infectious virus in cell culture may be very reasonable to use in a research laboratory, but would not be suitable for widespread commercial release. Furthermore, accuracy is more important for an assay that will be used to make medical decisions about a patient, as opposed to one used for laboratory experiments.”

Test developers have also identified a lack of access to blood samples positive for Zika virus antibodies—which are needed to validate whether serological tests are performing as expected—as a significant barrier to advancing the development of their products. To overcome this obstacle, the HHS office for preparedness and response has announced a program to support the collection of blood samples from people in the continental United States and Puerto Rico who have been infected with Zika virus.17

Under the 6-month, $692,000 project funded by the HHS Biomedical Advanced Research and Development Authority (BARDA), Clinical Research Management Inc, Hinckley, Ohio, will collect blood samples from people who have had confirmed Zika virus infection, in coordination with state and local health departments and CDC. The samples will be made available to diagnostic companies for use in validating the performance of their tests.

Richard J. Hatchett, MD, Department of Health and Human Services.

Richard J. Hatchett, MD, Department of Health and Human Services.

“Accurate diagnostic tools are vital for healthcare providers and their patients to determine whether people have been infected with Zika, especially pregnant women and their partners,” says Richard J. Hatchett, MD, acting director of BARDA. The new program “will help ensure manufacturers will have access to resources they need to improve and ensure the accuracy of their diagnostic tools and help us better protect our nation against Zika,” says Hatchett.

Moving toward the use of advanced technologies such as high-throughput sequencing raises interesting possibilities for infectious disease testing, but also suggests the question of whether those advanced systems are ready for everyday application in such routine uses. Lazear notes that high-throughput sequencing yields much more information than current diagnostic approaches. “In many cases this could be valuable, but in others that additional information may not meaningfully alter decisionmaking compared to currently available approaches. It will be a challenge to analyze and organize this new information in a way that is useful to clinicians and patients,” she says.


Many laboratories and IVD manufacturers have announced that they are in the process of developing either molecular or serological tests to detect the Zika virus. But in the United States, no tests with FDA clearance or approval have yet been brought to market. The handful of tests that are available to be ordered by clinicians are mostly under some restrictions on use, such as research use only status. Below are descriptions of a few tests whose availability has been announced.

A Texas LDT. In just a matter of weeks, a viral diagnostics program supported by philanthropists in Houston was reported to have developed a rapid, hospital-based test to diagnose Zika virus. But the developers encountered an obstacle when their press release suggested that the test might be available for use by others. “At the current time, only registered patients at Texas Children’s or Houston Methodist hospitals can receive the test, but the labs will consider referral testing from other hospitals and clinics in the future,” said the February release.

At the beginning of March, FDA signaled its intent to control the promotion and market release of such laboratory-developed tests for the Zika virus, by sending a letter to the principal developers of the Zika Direct Test. “We believe you are offering a high-risk test that has not been the subject of premarket clearance, approval, or emergency use authorization review,” the agency wrote. “FDA would like to better understand the test’s design, validation, and performance characteristics, and in addition, CDC and CMS have asked us to review the science behind your test.”18,19

One-Stop Shopping. Sometimes it’s necessary to cast the net widely in order to capture as many fish as possible. That’s the strategy adopted by researchers at Howard Hughes Medical Institute (HHMI), Chevy Chase, Md, who last year announced an inexpensive blood test called VirScan that is designed to reveal every virus that has passed through an individual over time. New technology developed by HHMI researchers makes it possible to test for past and current infections with any known human virus by analyzing a single drop of blood. Key features of the test include the following.

  • Scientists can run a single test to determine which viruses have infected an individual.
  • VirScan works by screening the blood for antibodies against any of more than 200 species of viruses known to infect humans.
  • The comprehensive analysis can be performed for about $25 per blood sample.
  • The test is currently used as a research tool and is not commercially available.

While not specific to particular arboviruses, the new approach has the potential to identify individuals who have been exposed to such viruses—even if their clinical symptoms were so mild as to be ignored.

Stephen Elledge, PhD, Howard Hughes Medical Institute and Harvard Medical School.

Stephen Elledge, PhD, Howard Hughes Medical Institute and Harvard Medical School.

“We’ve developed a screening methodology to basically look back in time in peoples’ blood and see what viruses they have experienced,” says lead developer Stephen Elledge, PhD, an HHMI investigator and professor of genetics at Harvard Medical School. “Instead of testing for one individual virus at a time, which is labor intensive, we can assay all of these at once. It’s one-stop shopping.”20

Enhanced Virome Sequencing. Eliminating the need for a library of viruses, a new test called ViroCap detects virtually any virus that infects people or animals. “With this test, you don’t have to know what you’re looking for,” says the study’s senior author, Gregory Storch, MD, the Siteman professor of pediatrics at the Washington University School of Medicine, St Louis. “It casts a broad net and can efficiently detect viruses that are present at very low levels. We think the test will be especially useful in situations where a diagnosis remains elusive after standard testing, or in situations in which the cause of a disease outbreak is unknown.”

Gregory Storch, MD, Washington University School of Medicine, St Louis.

Gregory Storch, MD, Washington University School of Medicine, St Louis.

Study results published last year demonstrated that in patient samples the ViroCap test can detect viruses not found by standard testing based on genome sequencing. The test could be used to detect outbreaks of deadly viruses such as Ebola, Marburg, and severe acute respiratory syndrome, as well as more-routine viruses such as norovirus and rotavirus, both of which can cause severe gastrointestinal infections.

Developed in collaboration with the university’s McDonnell Genome Institute, the test sequences and detects viruses in patient samples and is just as sensitive as the gold-standard PCR assays, which are used widely in clinical laboratories. However, even the most expansive PCR assays can only screen for about 20 similar viruses at the same time.

The Washington University researchers are making their technology publicly available to scientists and clinicians worldwide, for the benefit of patients and research. Their research is funded by NIAID.21

Mosquito-Borne Panel. Molecular diagnostics innovator Luminex Corp, Austin, Tex, is collaborating with the biomedical sciences institute of the University of São Paulo to validate a multianalyte arbovirus assay developed by Luminex partner, GenArraytion Inc, Rockville, Md.

The MultiFlex mosquito-borne panel is a qualitative nucleic acid assay that uses the Luminex 100/200 or Magpix instrument to simultaneously test for a broad array of the most common mosquito-borne disease agents, including chikungunya virus, dengue virus (DEN-1, DEN-2, DEN-3, DEN-4), Plasmodium falciparum, West Nile virus, yellow fever virus, and Zika virus (four genetic targets). The MultiFlex mosquito-borne panel is currently available as a research use only assay.

Luminex is providing a Magpix fluorescent detection system while partnering with GenArraytion to provide test kits for the University of São Paulo to validate the assay with clinical samples.22 Luminex is an exclusive distributor of GenArraytion’s MultiFlex bioassays.

Roche Test for Blood Screening. At the end of March, Roche, Basel, Switzerland, announced that it had been granted permission to initiate testing for Zika virus at US blood centers under an FDA investigational new drug study protocol.23 The Cobas Zika test for use with the Cobas 6800 and 8800 systems is a qualitative in vitro nucleic acid screening test for the direct detection of Zika virus RNA in plasma specimens from individual human blood donors.


Roland Diggelmann, Roche Diagnostics.

“The Cobas Zika test has been specifically designed utilizing the generic Cobas Omni utility channel on the Cobas 6800 and 8800 systems,” says Roland Diggelmann, chief operating officer at Roche Diagnostics. “These fully automated high-volume systems provide solutions for blood services to detect the virus and ensure that potentially infected blood units are not made available for transfusion.”

Initially, the Cobas Zika test will be deployed to screen blood donations collected locally in Puerto Rico. It is expected that this testing will enable the reinstatement of blood services in Puerto Rico and reduce the territory’s reliance on blood importation from other areas in the United States. The second stage of deployment for the Cobas Zika test will be to prepare for screening of blood donations collected by blood services in the southern United States, which will most likely be the first areas of the US mainland to be affected by any spread of the virus. 

EuroImmun Tests Get CE Mark. EuroImmun AG, Lübeck, Germany, has developed the first system of comprehensive tests available for the serological detection and differentiation of Zika virus infections. The tests were granted the CE mark in February, making them eligible for sale in the European market. They are available in the United States under research use only labeling.24

The EuroImmun anti-Zika virus tests, formatted as an enzyme-linked immunosorbent assay (ELISA) and an indirect immunofluorescence assay (IFA), allow for detection of specific antibodies (IgM and IgG) in the blood of those who may be infected. The tests provide a longer window for detection than the currently available quantitative PCR-based assays alone, making them particularly useful for disease surveillance. They can be used to diagnose patients with acute symptoms and to manage asymptomatic cases that fit a risk profile, particularly pregnant women.

The highly specific viral antigen used in the EuroImmun ELISA eliminates crossreactivity with other flavivirus antibodies, ensuring reliable differentiation from diseases such as dengue fever. The fully automated antibody detection test kits are suitable for rapid screening of large patient volumes and therefore provide efficient and effective monitoring of the virus spread.

Katja Steinhagen, EuroImmun AG.

Katja Steinhagen, EuroImmun AG.

“We have responded immediately to the growing concern of travelers and especially pregnant women around the world who have visited regions where the virus poses a potential risk,” says Katja Steinhagen, head of the ELISA infectious serology department at EuroImmun AG. “The ELISA and IFA tests have been evaluated in cooperation with the WHO Collaborating Center for Arbovirus and Hemorrhagic Fever Reference and Research, in Hamburg, Germany. Positive test results are a clear indicator of a Zika virus infection; our unique immunofluorescence mosaics enable laboratories to effectively evaluate samples for other viral fever diseases in parallel.”

Quest Granted EUA. At the end of April, Quest Diagnostics, Madison, NJ, became the first commercial lab to receive FDA emergency use authorization (EUA) for Zika virus testing of patients in the United States, including Puerto Rico.25 The Zika Virus RNA qualitative real-time RT-PCR test (Zika RT-PCR test) was developed by the reference laboratory business of Quest subsidiary Focus Diagnostics Inc, San Juan Capistrano, Calif. The proprietary molecular test is intended for the qualitative detection of RNA from the Zika virus in human serum specimens.

Previously, the only Zika tests to receive an EUA were available from CDC and were used only in qualified laboratories designated by CDC. Quest Diagnostics announced that it would make the new test broadly available to physicians for patient testing at the beginning of May.

Rick L. Pesano, MD, PhD, Quest Diagnostics.

Rick L. Pesano, MD, PhD, Quest Diagnostics.

“The availability of our new molecular Zika test provides physicians broad access to a diagnostic tool for managing the Zika outbreak,” says Rick L. Pesano, MD, PhD, vice president for research and development at Quest Diagnostics. “Quest’s expertise in molecular, infectious disease, and women’s health diagnostics, and relationships with half of the country’s physicians and hospitals, allow us to quickly make useful tests widely available for clinical use. This capability uniquely positions Quest to complement the response of public health laboratories for Zika outbreaks where access to FDA authorized diagnostic tests can potentially influence the quality of patient management.”

The EUA authorizes qualified laboratories designated by Focus Diagnostics and, in the United States, certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA) to perform high complexity tests, to perform the Zika RT-PCR test. The test can potentially be performed at any of several dozen high-complexity laboratories in the Quest Diagnostics network. For now, the test will be performed only at the Focus Diagnostics reference laboratory, which developed and validated the test.


For researchers seeking to understand the effects of Zika virus infection—and clinicians attempting to treat Zika-infected patients—the past year has been one of continuous revelations. In the United States, public health authorities have taken the lead on testing for the disease, using early versions of RT-PCR tests, CDC’s Zika immunoglobulin M antibody capture ELISA (with emergency use authorization), and confirmatory culture testing.

But with more and more clinical labs and IVD manufacturers paying attention to the challenges of creating diagnostic tools for Zika testing, the diagnostic landscape seems certain to undergo significant changes in the year ahead. And, if the Zika virus continues its march northward to the US mainland, the arrival of more advanced diagnostic tools for use by clinical laboratories won’t come a moment too soon.

Gary Tufel is a contributing writer for CLP. For further information, contact CLP chief editor Steve Halasey via [email protected].


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  1. Wylie TN, Wylie KM, Herter BN, Storch, GA. Enhanced virome sequencing through solution-based capture enrichment. Genome Res. Published online September 22, 2015; doi: 10.1101/gr.191049.115. Accessed April 28, 2016.
  1. Luminex corporation announces collaboration with University of São Paulo to validate Zika virus detection panel [press release]. PRNewswire. February 25, 2016. Available at: Accessed April 28, 2016.
  1. Roche to initiate testing for Zika virus at US blood centers under FDA investigational new drug application protocol [press release]. Basel, Switzerland: Roche, 2016. Available at: Accessed April 28, 2016.
  1. First commercial serological tests available for Zika virus infection [press release]. Lubeck, Germany: EuroImmun AG, 2016. Available at: Accessed April 28, 2016.
  1. Zika test from Quest Diagnostics authorized by the FDA for emergency use [press release]. Madison, NJ: Quest Diagnostics, 2016. Available at: Accessed April 28, 2016.