Ill Winds...

When I came back into the US there were a bunch of signs about zika - the mosquito-borne virus that has been much in the news of late.

Zika is in the news because it can cause severe birth defects. Congenital Zika Syndrome includes microcephaly (in some cases including partial skull collapse), decreased brain tissue, eye damage, limited joint motion and excessive muscle development prior to birth. Pretty nasty - microcephaly can lead to seizures, vision and hearing problems (vision problems are particularly common here because there may also be damage to the eyes) and developmental disabilities. And the rate is high, at least 10 percent.

So, evil horrible virus, let's wipe it out like we did smallpox.

Brakes on.

Apparently, zika is more like one of those toxic plants - it can poison you or, in the right dose, used the right way, save your life.

The reason zika causes all of those defects is because it attacks stem cells in the brain. Pretty bad if you're an infant.

If you're an adult, though, then you shouldn't have many stem cells in your brain. If you do, then that's bad - because it means you have aggressive brain cancer.

So, apparently, we may be able to infect somebody's brain with zika to kill the stem cells that create tumors, probably when we do surgery to remove the big ones.

(It's worth noting that one of the most potentially useful viruses to insert genes into human cells for gene therapy is...HIV).