I'm pleased to hear that you've solved the fingernail mystery. That must be a great relief to finally know what happened (sorta...lol).
I just wanted to add that having parasites is not abnormal, for adults or children. Most people reading this probably have a few parasites living in their bodies right now. This is one of the reasons why you hear about so many of us doing herbal cleanses. Included in all of the other health benefits, we're desperately trying to rid ourselves of different parasites that we pick up in a variety of different ways including, but not limited to, our diets, our pets, swimming, etc. I would imagine that young children are even more prone to have them as they touch whatever interests them without regard to how sanitary it is and, unless we catch them, they rarely wash their hands before putting them in their mouths or eating. I'm not familiar with the particular parasite that you speak of, but I do know that parasites, in general, are common.
Also, I 100% know what you mean on the relationship between spelling/grammar and intelligence. My husband is an extremely gifted (and I do mean extreeeeeemely) business man who can't spell to save his life. He speaks well, but when it comes to writing with any sort of grammatical accuracy, well...let's just say that he's thankful he has me to clean it all up for him.
Rarely a day goes by that he doesn't ask me to draft a letter/email for him or to edit something he's written. He makes an excellent living, has travelled the world, receives lots of press for his accomplishments, is in the process of publishing a book, is often invited to speak to groups and regularly instruct others on business strategies. I, on the other hand, can write my butt off, yet I can't even understand half of what does on a daily basis. lol
His personal assistant is almost as business savvy as he is and has long term goals of running for the U.S. Senate. There have been plenty of instances, however, where I've had to make serious edits to drafts he prepares.
Both of these guys are intelligent, super productive high achievers, but lack much when it comes to spelling and grammar. So, please know that there are those of us on these boards who understand the difference between intelligence and spelling.
Besides, at the end of the day...it's just a message board! lol