Ok, I just watched this video and am freaked the hell out.

http://www.youtube.com/watch?v=kXzFDtxp-Vk

How do you know if you have this?

In what part of the world can this happen? Is there a test that you can do to see if this has happened to you? I mean, how would someone even realized this had happened, it's not like you can feel inside your nose.

I realized maggots can be used medically to eat away at gangreen and diseased tissue, and I've even heard of botflies laying larva in the skin. But in your nasal cavity? Seriously?

This happens in tropical regions when flies lay eggs in moist body parts including inside a person's nose. I would guess there would be a tickling feeling and maybe a stuffiness.

Haven't you ever seen videos of people in Africa and India and other parts of Asia with flies crawling all over their faces?

So this only happens in tropical regions?
Yes, primarily -- in tropical regions where the climate is damp and heavy with many flies and other insects. (This video was taken in India.) Flies want to lay eggs in moist and/or foul material, which includes muscous-y areas of the human (and animal) body. Inside a nose qualifies. I would guess the man in the video has or has had maggots in other parts of his body too.

I wouldn't expect to find such a thing in a temperate climate unless the person's body is in very poor condition, there are hot and moist weather conditions (like now in the Chicago area), and the body is in an area where flies can get to it.

I'll PM Sneezy. He's one of our resident medical experts, is studying to be a doctor, and has spent time in the morgue plus reading about such phenomena.

If you read the information directly under the video you will see that these are not just any flies but screw worms (http://en.wikipedia.org/wiki/Chrysomya_bezziana#Geographical_distribution), which do not live in the US, where I am assuming you are.

If you live in any of these areas, use mosquito netting at night.

EDIT: To be more clear, ordinary house flies do not do this.

Thanks to WG for the link.

This condition is called Nasal Myiasis... and it generally occurs when the fly lays eggs inside the nasal cavity. Now, a nasal myiasis is VERY rare, as the fly would have to somehow crawl up the nasal cavity in order to lay eggs.

WG was right in that this primarily occurs in tropical areas, but more so, in areas where sanitation and hygiene is not roughly up to standards. The video you just watched is from an older patient in India. Generally speaking, if there's a fly in your room/house/wherever you sleep, it would be absolutely RARE for it to fly up your nostril and lay eggs. If anything, you would know that it was trying to fly up your nostril.

If you DO have this condition, you would definitely feel the larvae moving around inside your nostrils, and you would have consistent nosebleeds, a "stuffed up" feeling, and sometimes pain.

Again, it's very rare, but it's not deadly, just very uncomfortable and kind of gross. No worries.

Thanks everyone for the information and the link. It was very interesting and brought me to some medical sites I didn't even know existed.