Field-based assay for Zika and related Flavivirus

Abstract

A rapid field-based diagnostic assay is urgently needed to help track and control the spread of Zika as well as flaviviruses epidemics in general. One of the first challenges is in properly diagnosing Zika infection. The diagnostic is challenging for several reasons: first, many infected individuals do not suffer severe symptoms and thus the precise diagnostic can be lost or mistaken with Dengue fever or Chikungunya. The second challenge for Zika detection is technical: current diagnostic tools lack sensitivity and specificity and the similarity with other flaviviruses can lead to cross reactivity, specially in serological tests in individuals with previous Flavivirus infection. In other words, Zika virus elicits immune responses that produce antibodies with a degree of similarity with other flaviviruses, such as in infections by Yellow Fever, Japanese Encephalitis and Dengue viruses. Although the infection by the virus tends to be asymptomatic, there have been reports of the involvement of the virus in the manifestation of Guillain-Barré Syndrome and an increase in cases of microcephaly in Brazil. Thus, reliable field-based diagnostic tests are needed to determine whether pregnant women have been exposed so doctors can monitor fetal development in infected mothers. They would also provide valuable information for epidemiologists tracking Zika and dengue, as well as helping policy health makers to establish effective control efforts. The present project aims: i. to develop and validate a diagnostic device with the support of patented and licensed technologies developed by the applicant researcher and its group team based at UNESP, Institute of Chemistry, through an international ongoing research cooperation agreement involving the University of Oxford and Oxford Impedance Diagnostic; ii. to find genetic markers in Zika virus complete genomes to produce specific immunodominant peptides, which will be aggregated to enzyme-linked immunosorbent assay (ELISA) and microchips essays validated in i; iii. to develop and validate ELISAs and microchips to detect Zika virus (Sandwich-ELISA and electro-analytical microchips) as well as the immune response to its infection (IgG, IgM and Competitive ELISA/microchips); iv. to perform virus surveillance in serum and urine samples from cities of four different regions of the country, assessing clinical and epidemiological aspects of the infections; v. to evaluate if spatio-temporal patterns impact Zika transmission; vi. to analyze complete genome sequences of Zika viruses retrieved from surveillance and to evaluate if genetic differences are related to severe manifestations. This project aims to integrate virus surveillance with the development of diagnostic tests and their further application on health services. (AU)