Do you live in close quarters with a pet?

[Mhmmmmm]

A large population of people have some form of parasite and don't even know it. Round worms are very common and can be passed from cat and dog to humans. Make sure your pet is wormed monthly and use good hygiene. Do not handle pets fecal matter. Wash hands after cleaning pets messes. The eggs of round worms are mainly passed on through the dirt and infected pets fecal matter. People are not the common hosts for round worms but it can happen. It is unlikely and a nasty thing but you may have a parasite.

[Mhmmmmm]

It looks like you are an expert on the subject. You have lived it. It was a very good thing you did by helping those kids. I did a lot of research on worms when I found one in my dogs eye. I had all of my dogs tested at the vet. Their fecal matter came back negative for worms. It does seem very rare. I was reading that the common house fly can lay eggs in the tear of a dog or person. I'm guessing that's how my dog got it. It was easy to treat. Luckily I caught it before it got really infected. I found out later he could have lost his eye if it went untreated. It is heart wrenching to see children infected with parasites. More than I ever wanted to know about worms but eye opening.

[sblythe]

I have been a physician in the US for 25 years and have only had one patient test positive for roundworm.  I have also worked in third-world countries where literally every child has roundworm and many have other intestinal parasites as well.  I wouldn't get too paranoid about having roundworm or others if you live in the US. Besides - roundworms are reddish and 2-3 inches long, and shaped like an earthworm.  If you pass one, tell your doctor.