TUESDAY, April 4, 2017 (HealthDay News) -- In order for the mosquito-borne Zika virus to cause birth defects, it must first cross an infected woman's placenta to infect the fetus.
Now, researchers led by Dr. Robert Linhardt of Johns Hopkins University in Baltimore say they've identified how Zika does this -- and possible ways to stop it.
Throughout South America, the Zika virus has so far caused thousands of cases of devastating birth defects, most often microcephaly -- babies born with a smaller-than-normal head and underdeveloped brains.
So far, only a few such cases have occurred in the United States, but infections are a concern as the summer mosquito season nears.
"We think Zika is going to come back with a vengeance this summer. That's why we are working really hard to understand Zika as best as we can, as fast as we can," Linhardt, a chemical biologist at Hopkins, said in a news release from the American Chemical Society.
According to the new research, the Zika virus may be able to pass through the placenta by binding to certain sugars on the surface of cells. It's a method that's similar to one used by the mosquito-borne dengue fever virus, the research team noted. Dengue and Zika come from the same family of viruses.
In a series of experiments, the research team found that a particular sugar on cells in the placenta, called chondroitin sulfate, appeared to bind tightly to Zika. This offers Zika a way into the placenta, the researchers said.
Armed with this knowledge, Linhardt's team is continuing its research to find a way to block interactions between Zika and placental sugars. The goal is a means of stopping the virus from causing birth defects.
In prior work, the Hopkins team used a "nanoparticle" to prevent the flu virus from invading lung tissue in mice, preventing the virus from making the mice sick. The researchers are hopeful a similar approach might work to help stop Zika from affecting the fetus.
Linhardt is expected to present his team's findings on Tuesday at the American Chemical Society's annual meeting in San Francisco. Research presented at meetings should be considered preliminary until published in a peer-reviewed journal.
The U.S. Centers for Disease Control and Prevention has more on Zika.