Visit Your Local PBS Station PBS Home PBS Home Programs A-Z TV Schedules Watch Video Donate Shop PBS Search PBS
NATURE Home Current Season Episode Index NATURE Shop Contact Us For Teachers
Video DatabasePuzzles & FunEpisode PreviewsAnimal Guides
Featured Program
Bloody Suckers

Once Bitten 1 | 2 | 3

Did your doctor provide pills, shots, etc. to prevent possible infections?

Yes. It felt like I had every vaccination jab known to medical science before the filming. Getting a bunch of those on one day makes you feel pretty terrible -- the immune system must wonder what has just been dumped on it. Then there was the usual anti-malarial pills. I had suffered malaria before, so was very careful to use those diligently.

The scariest possibilities are the mosquito-borne diseases for which there are no shots or good treatments, like Dengue and Ross River fevers. They are both scourges of wildlife crews who work in the tropics a lot. Also Chagas disease carried by the South American "kissing bug" is bad because the symptoms are not always obvious and can show up 20 years later. That was why I only let myself get bitten by a clean, lab-raised bug.

Ferns received numerous vaccinations before allowing himself to be bitten.
Did you get ill during or after the production due to any of the bites?

Well to be honest, I felt pretty awful by the end of a year's shooting. But all the medical tests turned out negative. It was more likely just a combination of jet lag and progressive tiredness after racing around the world and spending months in the tropics, when I was not totally acclimatized.

Of course, I worried about unknown diseases that cannot be tested for. For instance, leeches have strong anti-bacterial chemicals in their gut so they don't transmit bacteria, but no serious research has ever been done on whether they carry viruses. But I'm pleased to say I feel much better these days.

Did any of the critters not cooperate?

Vampires were one of the toughest assignments. We spent weeks waiting all night trying to video wild vampires feeding on cattle and eventually, humans, because they are so cautious they do everything they can to avoid the subtlest lights (even moonlight). You might notice them onscreen scurrying from shadow to shadow.

When we used infrared cameras (with no visible light) they were still very cautious and could always tell where the crew was hidden, probably finding us with their echolocation.

Apparently, they often wait for hours, checking breathing patterns to confirm that victims are asleep. They typically bite between 1am and 4am, when victims are in their deepest sleep. Not surprising, when you consider that they get swatted, stomped on, or even shot at if caught in the act! They often bite sharply, then jump away, only to return when the victim is quiet and the wound is still bleeding. Then they lick gently like a cat lapping milk.

Eventually, I decided there was no point hiding the crew. Instead we waited till they got confident enough and hungry enough to bite me in plain view, so long as I pretended to be asleep.

The other tricky time was the leech bites. Not that it was difficult to get them to bite, but it was difficult to stop the wounds from bleeding afterwards. We wanted to get different angles plus slow motion and "time-lapse" versions of the leech feeding, so we used lots of leeches and they made lots of wounds on my arms and legs. For the extreme close-ups, my limbs often moved too much, so we had to tape my arm or leg to a table or chair for 40-minute stretches, which was uncomfortable.

Leeches have strong anti-coagulants in their saliva designed to keep the blood flowing steadily, sometimes six or eight hours later. Despite being wrapped in cotton wool and bandages, the little triangular wounds would still be bleeding and seeping through your clothes. That made it a bit messy and embarrassing going out to dinner at the end of a day's leech filming.

<< Back  Continue to Page 3 of 3

Once Bitten
Read an interview with Mark Ferns

Leech Therapy
Discover modern medical uses for leeches

Death Angels
How mosquitos spread West Nile virus

For Teachers
View the BLOODY SUCKERS Lesson Plan

Web links and books about bloodsuckers

56 T1 RealPlayer episode homepage