Genomic Precision

 A SeraCare blog focused on precision medicine and advanced clinical diagnostics

Improve the Reliability of Your Zika Diagnostic Assays

Robust molecular and serology reference materials for Zika diagnostic assays

Posted by Vidya Murthy on May 19, 2017 1:45:00 PM

What is Zika?

Zika virus (ZIKV) is an arbovirus that was first isolated in 1947 in a rhesus monkey from the Zika forest of Uganda. Until 2007, only 14 human cases were reported. The first large human outbreak occurred in 2007 (Yap Island, Micronesia, Pacific) followed by French Polynesia in 2013 that resulted in more than 30,000 cases. In early 2015, the virus came to international attention due to the outbreak in Brazil. Since then the epidemic has spread to more than 50 countries in the Caribbean, Central, and South America, causing tens of thousands of infections.


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ZIKV is transmitted to people primarily through the bite of an infected Aedes species mosquito (Ae. aegypti and Ae. albopictus). These are the same mosquitoes that spread dengue and chikungunya. ZIKV can also be transmitted sexually and during pregnancy from the infected mother to the fetus.

Symptoms include low-grade fever, maculopapular rash, conjunctivitis, joint pain, muscle pain and headache. During the recent outbreaks in French Polynesia and Brazil, ZIKV infection has been shown to be associated with two major complications; microcephaly and Guillain-Barré syndrome. In addition, ZIKV has been associated with hearing deficits, impaired growth as well as several other neurological diseases such as congenital eye disease in infants, uveitis, myelitis and meningoencephalitis in adults.

Given the fact that the treatment for Zika infection is only symptomatic and no specific anti-viral treatment is currently available; the scale of the recent outbreak in Brazil, has given rise to fears of further global spread of the virus. In February 2016, the World Health Organization declared the Zika epidemic a public health emergency of international concern and identified the development of reliable and accessible diagnostic tests a priority.

To halt the spread of this infectious disease, molecular and serological assay developers, researchers and clinical laboratories have to rapidly develop, validate and manufacture for global distribution, diagnostic assays that are accurate, precise and clinically relevant.

How can Zika be tested?

SeraCare Life Sciences offers serological and molecular reference materials for immunoassays and real-time PCR assays that can be successfully applied to develop, optimize and monitor Zika assays in the most reliable, robust and timely manner.

Zika IgM and IgG Antibody Positive Plasma

Naturally occurring human plasma samples from donors that have been tested and found positive for Zika IgG or IgM antibodies is one reference material that can support assay development. These specimens can be used by diagnostic manufacturers and clinical laboratory staff to evaluate assays that determine incidence (new acute infection) vs. prevalence (long-standing infections). These specimens are well-characterized by Centers for Disease Control and Prevention (CDC) approved algorithms and are useful for comparative analysis. 

Recent US Food and Drug Administration (FDA) safety communication underscores the significance and importance of using reliable reference materials. In Dec 2016, the FDA alerted physicians who care for pregnant women, meeting CDC Zika virus clinical criteria and/or CDC Zika virus epidemiologic criteria, that  the commercial testing currently available reports a “presumptive positive” indication and requires confirmatory testing as performed by the CDC.  The CDC confirmed less than half of the presumptive positive results.

More recently, in Feb 2017, FDA authorized Abbott’s molecular test to detect Zika virus in whole blood (when collected alongside a patient-matched serum or plasma sample) for emergency use. Abbott is also developing serology tests for Zika that do not cross-react with other tropical disease antibodies.

These reports illustrate the importance of reliable serological reference materials for accurate diagnostic tests, which is critical for successful control of epidemic outbreaks of Zika.

SeraCare’s AccuSet™ Zika Performance Panel, comprised of highly characterized Zika IgM plasma specimens collected from infected individuals, will enable assay developers to evaluate and validate new test methods and equipment. These tests are particularly helpful in the diagnosis of Zika infection. Click here to find out more about this product or contact us

AccuPlex™ Recombinant Zika Virus Linearity Panel

Accuracy and precision are key to the successful and rapid development of molecular diagnostic RT-PCR assays. SeraCare Life Sciences develops, manufacturers, and markets proprietary AccuPlex™ Zika virus reference material and a linearity panel to assist in the development and validation of molecular diagnostic assays to the virus.

The AccuPlex™ recombinant Zika virus is a mammalian RNA virus that closely mimics the Zika virus in both size and complexity. It contains the entire RNA genome of the ZIKV 2007 strain in four separate overlapping virus constructs. Each construct’s engineered genome length and its tertiary structure are similar to those of the Zika virus. In addition, The AccuPlex recombinant Zika virus is fully encapsulated like the pathogenic virus in a patient’s sample, so the product must go through an extraction process before nucleic acid detection, but the virus is replication defective as it lacks the genes required to produce new viral particles.  Furthermore, the virus is heat-treated, to assure that the virus is non-replicative, without interfering with target detection in a diagnostic molecular assay.

The use of AccuPlex™ Recombinant Zika virus reference material has many advantages over other technologies which package the viral RNA into a non-mammalian virus particle and may not represent the complexity of the Zika virus found in patient samples.

Fast-track the development of your molecular tests and assays against the Zika virus with this safe, non-infectious and fully extractable AccuPlex™ Recombinant Zika reference material! To find our more about this product click here or contact us today. 

Stay tuned for more information on the NEW AccuPlex™ Zika Linearity Panel that will help clinical laboratories to optimize and monitor their Zika molecular assays in the most reliable, robust and timely manner.

Want to learn more about the technology? Read our white paper, AccuPlexTM Technology for Rapid Development of Molecular Diagnostic Assays in Response to Viral Infectious Diseases

Download AccuPlex White Paper

References:

https://www.cdc.gov/zika/

https://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedical

https://www.europeanpharmaceuticalreview.com/

http://www.prnewswire.com/news-releases/ 

Topics: Accuplex, zika virus, Blood screening, Women's health, pregnancy womens testing

 
 

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