Zika Is More Than Microcephaly
Until recently, Zika transmission in the US was limited to Florida. But we all knew that wouldn't last. It then showed up in the Rio Grande Valley near Brownsville, Texas, and by the summer of 2017, Zika will have spread further.
We've known about Zika since 1947 when it was first isolated in Uganda, Africa. It spread from there to SE Asia, Micronesia and finally South and Central America and the Caribbean. The attention the summer Olympics brought to Brazil, an epicenter of this infection has heightened the concern, especially the risks posed to newborns.
An infected pregnant woman can give birth to a baby with a small head and brain called microcephaly. Many of these children do not survive into adulthood.
A study in the journal Radiology has begun to identify some signs that microcephaly is evident early in pregnancy. Right now, this diagnosis can only be made in the late second to the third trimester.
The study found that brain images reveal structural changes in the corpus callosum that controls communication between the two hemispheres of the brain. As early as the second trimester, images also show changes in the regions affecting speech, movement, thought and emotion. Another especially damaging effect are the calcium deposits that occur between the cortex, the brain's outer layer, and the underlying white matter. This affects learning, memory and coordination.
Not only can these changes cause microcephaly, they could also result in other brain damage. We will be unaware of the full impact of the Zika virus on children until their brains reach full maturity at age 25.
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