A Rapid, Low-Cost Point of Care Diagnostic for detection of Zika virus RNA

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ABSTRACT Zika virus (ZIKV) has rapidly emerged and spread through South and Central America, the Caribbean, and Puerto Rico since its last outbreak in Micronesia in 2007. Transmitted by the mosquito Aedes sp, its forecasted spread will have a major impact on the Southeast U.S. Most ZIKV infections remain asymptomatic or present with non-specific rash and fever; therefore, they have been difficult to diagnose and report. However, two major health consequences appear to be associated with the ZIKV outbreak which sets it apart from other flaviviruses such as West Nile Virus and Dengue; namely; (a) transmission from an infected mother to fetus resulting in reports of microcephaly in fetuses; and, (b) Guillain-Barre syndrome (GBS) in adults. Several teams have now developed qRT-PCR assays to detect ZIKV. However such tests are relatively expensive, require well-equipped laboratories with specialized equipment, and the procedure takes at least 3 hours to finish. There is an urgent need for a rapid, sensitive, specific and economical diagnostic test for ZIKV. Such an assay could be routinely used in resource-poor settings as well as in doctors' offices, including as part of regular prenatal care. Therefore, the goal of the SBIR Phase I project is to use loop mediated isothermal nucleic acid amplification (LAMP) to develop a rapid, sensitive point of care diagnostic for ZIKV. This technology is of low complexity, requiring only a water bath. Colorimetric results are visible to the naked eye in one hour or less. We will use serial dilutions of ZIKV and other viruses (including West Nile virus, Dengue viruses, and Chikungunya virus) spiked in human blood, saliva, and urine to determine the assay's sensitivity and specificity. Based on our laboratory's extensive previous experience with LAMP assay development, we forecast a lower limit of detection of 10-100 viral genomes, with very high specificity. In addition to rapid, colorimetric ZIKV detection, we will also develop a rapid, lateral flow assay to facilitate the differential analysis with other flaviviruses. The development of rapid point-of-care assays will reduce the dependence on central laboratory testing facilities for epidemiologic surveillance and clinical diagnosis, a key advantage in the resource-poor areas where the epidemic is currently prevalent. Further, we anticipate that the availability of a rapid test will result in the incorporation of ZIKV testing into the sustainable, routine evaluation of women who are pregnant or anticipating pregnancy, as well as their partners.