The Ebola virus might elude immune responses by stopping a key protein in infected cells from activating defence genes.

Ebola, which kills up to 90% of people it infects, is known to disrupt the activity of interferon, a crucial antiviral protein. Gaya Amarasinghe at Washington University School of Medicine in St Louis, Missouri, and his colleagues found that an Ebola viral protein blocks the transport of an interferon-activated protein called STAT1 into the cell nucleus. STAT1 is needed in the nucleus to stimulate defence mechanisms.

The results suggest new drug targets in the ongoing fight against the virus.

Cell Host Microbe 16, 187–200 (2014)