Belinda Smith

So the way that I got infected and the way we infect all the people in our clinical trials is we take worms that have been cleaned up and made as sterile as possible and we put them in a little drop of water and we put them on the skin.

For me and for a lot of our volunteers, it's on the forearm.

We'll put a small drop of water on the forearm and within seconds those larvae detect the skin and they actively burrow through it.

Yum, I mean, or rather yuck, depending on which side you're on.

But the fact that they manage to survive, they're doing things to the human body which means that they're sustainable and in some ways it's good for you.

In what way?

So these worms are purely selfish little buggers.

All they want to do is sit in your gut, eat, have sex and stay there for years.

They're separate males and females when they're adults.

They find each other and they pretty much mate for most of their life consistently.

And the female will produce about 10,000 to 15,000 eggs per day, each female worm.

So when she releases those eggs, they're released into the lumen of the bowel and they come out in the faeces.

And an infected person in a developing country, if they don't use a toilet, if they defecate in the environment, which is still quite common in a lot of rural areas, then the eggs that come out in the faeces will...

embryonate, and if it's a warm, humid environment, eggs will hatch and the little larvae inside will burrow around in the soil for a while, eat the bacteria, undergo a couple of molting cycles like an insect, cast off their outer sheath, get a little bit bigger, and they do that twice, and that's the stage that then is ready to encounter human skin.

So if someone sits on the ground where these larvae are hanging around or if they walk barefoot,

that brief encounter is enough for the worms to grab hold of the skin and start burrowing through.

And that often goes unnoticed.

Or when I got infected, and when our volunteers in clinical trials get infected, they experience intense itchiness.

It's not pain, it's just intensely itchy.

And then once those larvae have gotten into the skin, they find the nearest blood vessel.