New York, Nov 19 (IANS): In a major step towards producing an effective vaccine against the deadly Zika virus, researchers have developed a way to replicate its basic structure, stripping it of the genes that make it infectious.

"One of these replicons can be used to locate portions of the viral molecule that block or halt viral replication, making it a powerful tool for vaccine development," said senior study author Pei-Yong Shi, Professor at The University of Texas Medical Branch in Galveston in the US.

The recent Zika virus outbreak has highlighted the urgent need to establish genetic tools for studying how the virus multiplies and causes disease within a newly infected person in order to develop countermeasures.

This is especially important because the Zika virus is spreading rapidly and behaves differently than many other viruses - for instance, it can be transmitted sexually and is associated with microcephaly, a birth defect that can lead to abnormal smallness of the head.

The new Zika replicon system, described in the journal EbioMedicine, deleted some of the genes that give the virus its structure. Because of this, the altered Zika virus is no longer infectious, lowering the safety risk involved in working with it.

The replicon system was engineered by attaching genes that allow researchers to tag certain parts of the virus that they are interested in.

Luciferase, the chemical that gives fireflies their signature glow, was used to make targeted viral components light up -- making processes like replication much easier to observe.

"Knowing when and how the virus is mutating is important, as evolution is what makes viruses more adept at invading hosts like humans or animals or become more damaging once inside the host," Shi said.