How does the Zika virus enter a developing baby’s brain? Neurologist Arnold Kriegstein and his team at the University of California, San Francisco recently found that the receptor protein used by Zika to cause a skin rash also sits on the surface of some developing neurons. The protein acts as a channel into what’s known as radial glial cells.

"This is a cell type that actually produces most of the nerve cells, the neurons, and also the associated cells in the developing brain, and it’s also the cell type that’s been implicated in genetic causes of microcephaly."

The team grew brain tissue in petri dishes and sent fluorescently labeled proteins into the samples. The glowing proteins then honed in on the these radial glial cells, pinpointing the receptors.

"Whether the virus is going through the bloodstream in the fetus, or if it’s going through the cerebral spinal fluid, it can directly access these radial glial cells. So it looked as though this receptor was a smoking gun. It seems to be in the right place at the right time, to explain the symptoms that we’ve been hearing about in Brazil."