Kephera -Diagnostic Testing Tools for Zika Virus Infection
Kephera is developing a test for Zika virus infection with support from a grant from the National Institutes of Health. Kephera’s Zika project is based on the identification of Zika-specific and Dengue-specific epitopes within the viral genome, from which an immunoassay will be developed in convenient and cost-effective ELISA format, and ultimately translated to point-of-care format. To this end, we are working in collaboration with medical research institutes in the U.S. and Latin America to analyze the immunological reactivities of patient sera from Zika and Dengue-endemic regions, using a variety of epitope mapping techniques. Epitopes selected based on ability to differentiate viral infections will then be expressed synthetically or as recombinant antigens for assay development.
Zika is transmitted by the same Aedes mosquito species that transmit the related Dengue and Yellow Fever viruses, along with a variety of others such as Chikungunya. As Dengue virus is endemic in much of the tropical world, background immunological reactivity to Dengue tends to confound the serological diagnosis of Zika infection. Accurate diagnosis of Zika infection in the post-viremic or convalescent phase continues to be a significant challenge, calling for the development of tests which are truly specific for this virus.
Zika emerged in 2015 as a major public health threat in the western hemisphere, leading to an urgent need for diagnostic tools for clinical and epidemiological use. Although primary Zika infection is typically accompanied by mild symptoms, the virus has been linked to severe birth defects in infants born to infected mothers, and to potentially fatal neurological conditions including Guillain Barré syndrome.
Zika infection can be detected by molecular assays, but this approach is only useful during the relatively brief viremic phase, typically several weeks or less. After this period, individuals including pregnant women at risk for complications caused by prior infection can only be identified by serologic assays. The close genetic relationship between Zika and other flaviviruses has made serological diagnosis extremely difficult, however, due to cross-reactivities between viral antigens.