Like Zika, West Nile virus causes fetal brain damage, death in mice. Jonathon Miner, MD, PhD, with help from Michael Diamond, MD, PhD, infected human placentas with one of four viruses or zika virus.

Two viruses closely related to Zika – West Nile and Powassan – can spread from an infected pregnant mouse to her fetuses, causing brain damage and fetal death, according to a new study from Washington University School of Medicine in St. Louis. The findings suggest that Zika may not be unique in its ability to cause miscarriages and birth defects.