UC Berkeley’s new assay differentiates Zika from other viral infections


The University of California (UC) Berkeley in the US has developed a new test to differentiate infections caused by Zika virus from those of other flaviviruses such as dengue and West Nile.

Developed in alliance with biotechnology firm Humabs BioMed, the cost-effective antibody-based assay possesses 91.8% sensitivity and 95.9% specificity for Zika virus detection.

Existing tests are said to work after infection and cannot precisely differentiate Zika from similar viruses, leading to the inaccurate determination of Zika infection prevalence, congenital Zika syndrome incidence, and frequency of Zika-associated neurological problems.

For the development of the new assay, Humabs used its CellClone discovery technology to produce a new human antibody with enhanced sensitivity and specificity for Zika.

"The whole world has been in urgent need of a serological method to distinguish dengue virus from Zika virus infections, and this is the first to have such high sensitivity and specificity in dengue-endemic regions."

UC Berkeley School of Public Health Infectious Diseases and Vaccinology division professor Eva Harris said: “The whole world has been in urgent need of a serological method to distinguish dengue virus from Zika virus infections, and this is the first to have such high sensitivity and specificity in dengue-endemic regions.”

When the assay was carried out in five countries with clinical samples from Zika-infected patients, as well as 540 patients with other flavivirus infections and healthy donors, specificity was 95.9%.

To avoid cross-reactivity, researchers also used patient samples from professor Harris’ collaborative studies in Nicaragua, Central America in Zika patients with or without prior exposure to dengue virus and samples from dengue patients who were infected one or more times with different dengue viruses.

According to Humabs BioMed senior vice-president and chief scientific officer Davide Corti, the new assay can potentially act as a simple solution for Zika surveillance programmes.