MICHAEL SMITH:
When a pregnant woman gets zika
virus, doctors believe it can
cause a serious, often fatal
birth defect called
microcephaly.
That means the baby's head
and brain are much smaller
than usual.
But they haven't known how zika
does its damage.
Now researchers have discovered
that it targets developing brain
cells.
These are stem cells that give
rise to the cerebral cortex,
the part of the brain that
controls speech, memory,
movement, and intelligence.
Zika doesn't kill them right
away.
Instead, it hijacks them
and uses the cells to churn out
even more of the virus
so it can spread faster.
And in the lab, at least,
it goes after these brain stem
cells much more
than any other cells.
People get
infected with the zika virus
through a mosquito bite.
It can also be spread
through sex.
Right now, the biggest danger
is when you travel.
If you're pregnant and have been
to Central America, South
America, or the Caribbean,
let your doctor know.
For WebMD, I'm Dr. Michael
Smith.
