May 2016

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Researchers Examine the Structure of Zika Virus

Scientists found a structural detail on the surface of the Zika virus that distinguishes it from similar viruses. Continuing to study this tiny difference might help researchers develop targeted therapies and better ways to diagnose Zika infections.

Zika virus is mainly transmitted to humans by the bite of infected mosquitoes. It’s in the same family of viruses—called flaviviruses—that can cause the mosquito-borne diseases dengue, yellow fever, or West Nile illness. Most people infected with Zika virus don’t get sick. If symptoms appear, they tend to be mild and go away within a week. Symptoms can include fever, rash, and joint pain.

But if a pregnant woman becomes infected with Zika virus, her unborn child may be at risk. Recent evidence confirms that Zika virus can cause severe fetal brain abnormalities, including microcephaly, a rare condition in which an infant’s head is unusually small.

To learn more about Zika virus, NIH-funded researchers examined its structure at near-atomic resolution. They used a technique called cryo-electron microscopy. The process involves freezing viruses and firing a stream of high-energy particles through the sample to create tens of thousands of images. These 2-D images are then combined to create a detailed 3-D view of the virus.

The 3-D images showed that Zika virus is structurally similar to other flaviviruses. But one difference in a protein on the virus surface may help it attach to and enter human cells. This detail might be something that researchers can take advantage of in efforts to develop Zika drugs or vaccines.

“The structure of the virus provides a map that shows potential regions of the virus that could be targeted by a therapeutic treatment,” says study co-author Dr. Richard Kuhn of Purdue University. The structure might also point to new approaches for vaccine development or improved diagnostics for Zika infection, the researchers say.