Anybody who has spent much time with children's literature knows that scarlet fever blinded Mary Ingalls.

But scarlet fever doesn't cause blindness.

Mary really did become blind, though, in real life as well as in the books, so what was the real culprit? A paper published this week in the journal Pediatrics speculates that it could have been viral meningoencephalitis — inflammation in the brain and in the membranes that surround the central nervous system.

There are several possible causes. In Europe and Asia, ticks can spread a virus that causes meningoencephalitis. West Nile virus can cause it, as well. So can the mumps. And so can herpes simplex type 1 — the oral herpes virus that is present in the vast majority of people.

Which means that this story not only has ties to the other Little House history pieces we've run here at Boing Boing — the meteorology of the Long Winter, and the crazy connection between the Ingalls' and a family of serial killers — it's also, possibly, another example of a heroine from children's fiction who had herpes.

The full paper, sadly, is behind a paywall. But The New York Times' Motherlode blog has a nice summary of it.

Anne of Green Gables had herpes. And now, you can learn a little more about how herpes hides out in your body and how it causes cold sores with the help of University of Texas professor Chris Sullivan, a bunch of legos, and a platoon of green army men.

Many thanks to Joe Hanson!