THE ZIKA VIRUS AND ITs DEVASTATING EFFECTS
https://wamu.org/story/16/05/11/how_the_zika_virus_damages_the_brain/
A few weeks
ago, Dr. James Bale saw a series of MRI images in a medical journal of MRI
scans of babies infected with Zika in the womb.
The scans
showed something Bale had seen only a few times in his 30-year career: a
phenomenon called fetal brain disruption sequence.
As the
fetus's brain starts to grow, it creates pressure, which pushes on the skull
and causes it to grow. But if something stops brain growth — such as a virus —
pressure on the skull drops. And the skull can collapse down onto the brain.
The skin
around the head continues to grow, Bale says. So the baby is born with wrinkles
of skin at the back of the neck and a tiny skull. In some cases, the baby's
head is as small as an orange, or about half the size of a healthy baby's head.
"It's
quite remarkable what the Zika virus is doing to the brain of young
infants," Bale says. "Many of them will die often in infancy, and the
majority, if not all, will then have a long-term, severe developmental
problems."
Zika Is
Linked To Microcephaly, Health Agencies Confirm
Now
scientists think they have an understanding about how Zika causes these severe
brain malformations. The findings come from a series of mouse experiments,
published Wednesday in three leading journals.
In one
study, published in Nature, Alysson Muotri and his team at the University of
California, San Diego, infected pregnant mice with Zika and looked to see how
the virus harmed the baby mice.
"We
detected the virus all over the mice and in different regions of the
body," Muotri says.
But for some
reason — and scientists don't know why yet — Zika is particularly attracted to
brain cells. And once inside the cells, Muotri says, Zika turns them into viral
factories that start producing huge amounts of virus. Until they burst.
"They
explode, and more viral particles are released that can infect other cells. And
they can just amplify themselves," Muotri says.
More and
more brain cells get infected. More die. This cell death is already a problem
for the fetus. It scars the brain and creates inflammation.
But the
situation gets worse because the brain cells infected by Zika are extremely
special. They're called neural progenitor cells. And they're responsible for
building a large portion of the brain.
"These
are fast-replicating cells that will give rise to billions of cells in our
brains," Muotri says.
So if a
fetus loses even just a small percentage of these cells, a portion of its brain
will never develop. "And the impact later in life would be dramatic,"
he says.
A second
study, published in the journal Cell Stem Cell, confirmed that Zika destroys
neural progenitor cells inside a growing embryo. In that experiment, a team of
scientists at the Chinese Academy of Sciences, injected the virus directly into
the brains of mice embryos, developing inside their moms.
Muortri says
death of brain cells is likely the major way that Zika causes microcephaly in
babies. But it isn't the full picture.
In the third
study, Indira Mysorekar and her colleagues at Washington University in St.
Louis, also infected pregnant mice with Zika.
They found
the virus not only damages the brain but also attacks the placenta.
"The
nutrient and blood exchange that normally happens between the mother and the
fetus is reduced," Mysorekar says. This slows down the baby's growth — and
may hurt the brain as well.
Mysorekar
and her colleagues published their findings in the journal Cell.
She says
mouse experiments can never tell us exactly what's happening in people. Human
anatomy is more complicated.
But one
thing is clear: Once Zika infects the fetus, "it leaves a lot of havoc and
devastation in its wake," she says. "It's almost like a tornado or an
earthquake. There is death following Zika."
In 2017, I wrote a Futiristic Thriller Series inspired by the Zika Virus.
A script for a Movie is being written.
Revenge of Zeeka: Five book Series
Read the Series on AMAZON.
.jpg)
