Zika virus has infected thousands of Americans and hundreds of them are pregnant women, putting their unborn babies at risk for a lifetime of a rare neurological condition known as microcephaly. The National Institutes of Health teamed up with researchers from Florida State University and Johns Hopkins University to search for a way to stop Zika from replicating in the human body and killing fetal brain cells.

For the study, published in the journal Nature Medicine, researchers explored the potential of two drugs approved by the U.S. Food and Drug Administration (FDA) that are already on the market. Their findings reveal the breakthrough drug called Nicolsamide, which is commonly used to treat tapeworm, effectively haults the virus, birth defects, and does not cause harm pregnant women. Although more tests are needed to tailor the drug to the Zika virus infection, Nicolsamide could, in theory, be prescribed by a doctor today.

"It takes years if not decades to develop a new drug," said the study’s co-author Hongjun Song, who specializes in degenerative neurodegenerative diseases at Johns Hopkins School of Medicine, in a statement. "In this sort of global health emergency, we don't have time. So instead of using new drugs, we chose to screen existing drugs. In this way, we hope to create a therapy much more quickly."

Because the virus causes severe damage to the unborn baby, leading them to develop microcephaly, research teams from around the world have been scrambling to find a cure before more babies are born with the debilitating disease. According to the Mayo Clinic, the condition causes developmental delays, difficulties with coordination and balance, dwarfism, facial distortions, hyperactivity, mental retardation, and seizures.

"It’s so dramatic and irreversible," said the study’s co-author Hengli Tang, a biological science professor at Florida State University, in a statement. "The probability of Zika-induced microcephaly occurring doesn't appear to be that high, but when it does, the damage is horrible."

Zika virus can be transmitted by mosquitoes or through a sexual partner, which is why by being able to stop the disease’s replication in the body and damage to the unborn baby’s brain cells, the rates of the disease are predicted to drop. Researchers turned to the pre-existing drug Nicolsamide in hopes it could be used to lay the foundation for a more permanent, long-term treatment.

"We focused on compounds that have the shortest path to clinical use," Tang said. "This is a first step toward a therapeutic that can stop transmission of this disease."

Source: Tang G and Song H, et al. Nature Medicine. 2016