A: Dear Sophie,

I know: worms are for gardens. The thought of some up the bum is enough to make us hurl.

But remember, this sounds much worse than it is. Bum worms are totally different to garden worms. For a start they are tiny. And white. Each one looks like a half-centimetre strand of cotton. Hence the name: threadworms.

Most of us get threadworms at some point. You may have had some and not even noticed. They often give us no bother. And cause no harm. If they do cause trouble it's usually nothing more than an itchy bum. Often worse at night.

How do we get them? Here's the biology.

Lifecycle of a Threadworm

• Eggs are swallowed

• Larvae hatch in our guts

• Worms lay eggs at the anus, causing itching

• We scratch our bums (often in our sleep)

• We put our fingers in our mouths or up our noses

• We touch taps, loo handles, etc.

• And on it goes.

So what to do?

1. Always wash your hands after going to the loo. And again before eating. Same goes for all of us. Oh, and quit nail biting or nose picking. Nasty habits.
2. If you have an itchy butt, ask your GP for advice. Mostly worms are killed with a single one-off tablet. Job done.
3. If your bum is happy - so should you be. Leave well alone.
4. Go hang with your cousin. She had worms, not bubonic plague.

*Dr Mel is a GP in east London

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