What possessed you to surrender your body like this?
Well, I was paid to do it! No, I've always been interested in how things work, and that goes back to my first career as a mechanic. After my degree in biology I specialised in viruses because I was interested in how they could hijack your defences and live inside your body. Viruses and bacteria are parasites, but they're relatively small compared to human beings - but the idea of something larger like a tapeworm that can thrive within another organism is truly gross. So finding out how they do that was my main motivation, and the best way to find out how something works is to try it yourself. And as not many people have done it, it struck me as a good idea. It was fun as well. I learnt a hell of a lot. It's easy to read things or see them on telly, but when you've got one growing inside you it takes on a whole new dimension.
How many have you experienced?
Oh crikey, I've never counted! Leeches, maggots, botfly larvae, headlice, fleas, body lice, the kissing bug, mosquitos, ticks... a dozen for this series. And I grew a tapeworm again.
Were you an old hand this time?
Not really. It grew differently. And I also had a competition with a mate - I brought a cyst home for him - so that was different. My wife's pregnant and expectant mothers get together with other pregnant women and go to antenatal classes. So what was nice this time was we had our own antenatal classes, watching TV and talking about feeling the tapeworms move and wearing incontinence underwear to make sure any bits that crawled out of our backsides didn't make a run for it.
Nice.
It is horrible.
Is that how they spread?
Pretty much. They break off the little eggs called proglotids - but we called them crawlers - so they can either be found in your crap or they make their own way out. They're an inch, an inch-and-a-half long and look like something you'd see in a Pot Noodle. And they can crawl out of their own volition. You just feel this tingly sensation and know one's on its way out and you have to visit a loo and deal with it.
And how do you persuade a botfly larva to take up residence in your body? They live inside a boil on your skin, right?
Right. It was a bit difficult. There was a mad professor near Rio de Janeiro in Brazil and we went to see him. The botfly is large and doesn't lay eggs directly onto its host, or it's liable to get squashed. It kidnaps smaller, faster-moving insects, lays eggs on them, and when they land on you the eggs sense the heat; the larvae hatch almost instantly and burrow into your skin. We used a paintbrush and painted on about eight larvae, but only one took.
How do you know you have one?
It's a mild itching. I felt it because I knew they were there, but you can see how they can infect you by stealth because you really don't feel that much, and they'll just disappear up into a hair follicle and grow there and you don't know anything about it for a couple of weeks.
And eventually they come out as a little fly?
They come out as a pupa. I think they're meant to grow for about five weeks, but it was in me longer than that. The thing is, nobody really knows. There's a lot in parasitology where people haven't got any hard facts. None of the experts knew exactly how long they'd grow for, or what the likelihood was of them taking, as not many people grow them on themselves. It's not really common practice.
How did you get rid of it?
It was cut out. It could make its own way out, but it wasn't doing very well as it got in behind my knee - it was in an area that gets rubbed as there's a lot of movement, so it got infected. It was likely to die inside me and that wouldn't have been very nice.
And your brother had a Tumbu fly?
Yeah, he had it on his arsecheek because he left his pants out to dry. In areas of central and west Africa, if you leave your clothes out the Tumbu fly finds it a nice place to lay its eggs, and if you don't iron them the chances are you could end up with a Tumbu fly burrowing into you. And in his case it was his arsecheek - which was funny.
It's the same, it grows a little boil?
Yes, they're distant relatives. His just dropped out. He didn't even notice it. But it was quite unsightly.
And hard to sit on.
Yeah, it was painful.
So was there one parasite, of all of them, you wish you hadn't tried?
EIGHT NASTIES THAT MIKE HAD LIVING IN HIM
Tapeworms
There are different species of tapeworm that can infect humans. The largest, the fish tapeworm, can reach a length of 30ft and live for up to 20 years. They don't usually threaten their host, but if they reach the central nervous system they can cause neurocysticercosis, which can result in seizures and may be life-threatening.
Leeches Leeches in infected waters attach themselves to exposed skin. They use two muscular suckers to attach themselves to the subject, then bite into the flesh with their three teeth. They absorb 10 times their weight in blood before dropping off.
Botfly Larvae
Usually introduced to a human host by a mosquito, botfly larvae live in a raised boil on their human host for up to six weeks. If you get infected by a botfly, you can extract it yourself. Use smoke to force its head out, or apply a thick layer of Vaseline over the boil to cut off its air supply; then, when its head emerges, yank it (gently, so it doesn't break off!) from the fleshy lump.
Maggots
The maggot is the larval stage of the fly. As well as dung and old plant matter, they eat rotten flesh. Historically, maggots were used in medicine to nibble at putrid wounds to rid them of dangerous infection. Today, 'maggot therapy' is being reinstated in many hospitals.
Headlice
The average adult headlouse is a couple of millimetres long. Lice bite through their host's scalp and feed on blood. Lice lay eggs, and the empty shells are what are popularly known as 'nits'. You can tell how long someone has had headlice by the distance of the eggs from the scalp - hair grows at 1cm per month, so if the eggs are 3cm away from the scalp, the lice have been there for three months.
Kissing Bugs
The kissing bug, or triatoma protracta, is a 0.75in bug that feeds on its human victims at night. It bites into the soft tissue of the lips, eyelids or ears and sucks the blood of the victim. Its saliva, which it injects into the victim during the feeding process, can cause severe allergic reactions. The creatures are also known to carry Chagas disease, a form of sleeping sickness.
Mosquitos
Mosquitos breed in standing water. Their bites become raised and itchy within the hour. They can carry diseases such as malaria and West Nile virus. Female mosquitos do the biting as males don't have suitable mouthparts.
Ticks
Ticks attach themselves to mammals to feed. They need a blood meal to mutate into their next stage of life. If left alone, they'll stay attached to their host for a week, engorging themselves with blood. They spread Lyme disease, Rocky Mountain spotted fever, and meningoencephalitis. Their bite can cause a severe allergic reaction and paralysis.
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