Zika in Placental Cells (IMAGE) Washington University School of Medicine Caption Human placental cells (blue) infected with Zika virus (green) responded to the malaria drug chloroquine (left). The drug prevented the virus from growing, unlike the drug rapamycin, which prompted the virus to grow rapidly (right). Studying pregnant mice, researchers at Washington University School of Medicine in St. Louis found that Zika virus manipulates the body's normal barrier to infection, and that hydroxychloroquine, a malaria drug related to chloroquine, interferes with this process, protecting the fetus from viral infection. Credit Bin Cao Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.