Original subtitles

Narrator: DEADLY ORGANISMS LURK ALL AROUND US.

WHEN ONE ATTACKS AN 11-MONTH-OLD BOY,

IT COULD BE DISASTROUS.

Tony: WE WERE ABSOLUTELY DEVASTATED.

IT WAS THE WORST DAY WE HAD EVER HAD.

Narrator: A VIETNAM VET SURVIVES THE GROUND WAR,

BUT CAN HE BEAT A HIDDEN ENEMY

THAT'S BEEN LIVING INSIDE HIM FOR YEARS?

THE PAIN WAS OUTRAGEOUS. I WANTED TO SCREAM.

Narrator: AND A FATHER HAS NO IDEA A KILLER IS LODGED IN HIS BRAIN.

THEY'RE LIKE, YOU KNOW, "WE NEED TO DO BRAIN SURGERY."

"GEE, THAT'S GREAT. JUST MAKE THIS STOP."

Narrator: THREE VERY DIFFERENT PARASITES,

THREE SLEEPER CELLS

LYING DORMANT UNTIL THEY'RE READY TO ATTACK.

-- Captions by VITAC -- www.vitac.com

WORMS INVISIBLE TO THE HUMAN EYE...

...INSECTS THIRSTY FOR BLOOD...

...MICROSCOPIC AMOEBA.

THEY MIGHT LOOK HARMLESS,

BUT THESE ARE SOME OF NATURE'S DEADLIEST CREATURES.

THEY CAN HIJACK OUR BODIES, DISABLE OUR IMMUNE SYSTEMS.

THEY ARE PARASITES.

BUT TO THOSE INFECTED...

THEY ARE "THE MONSTERS INSIDE ME."

CAPTIONS PAID FOR BY DISCOVERY COMMUNICATIONS

PARASITES ARE THE MOST SUCCESSFUL ORGANISMS

ON THE PLANET.

THEY LIVE IN OR ON OTHER LIVING CREATURES CALLED HOSTS.

IN A PARASITIC RELATIONSHIP, THERE HAVE TO BE TWO PARTIES.

THERE'S A HOST THAT LOSES,

AND THERE'S A PARASITE THAT WINS.

THERE ARE COUNTLESS ORGANISMS THAT MAKE A LIVING OFF OF US.

Narrator: WE CAN'T ALWAYS SEE THEM

BECAUSE THEY'RE LIKE SLEEPER CELLS --

PERFECTLY ADAPTED TO LIVE UNDERCOVER,

FEEDING, GROWING, AND BREEDING.

TICKING BIOLOGICAL TIME BOMBS,

THEY LIE DORMANT UNTIL IT'S TIME TO STRIKE.

Riskin: FOR A LOT OF PARASITES,

AN IMPORTANT PART OF THE LIFE HISTORY, OR THE LIFE CYCLE,

IS TO HIDE AND WAIT.

THERE IS ALWAYS SOME KIND OF AN ENVIRONMENTAL CUE

THAT IS GOING TO TELL IT THAT NOW IS THE TIME TO ACT

THAT IS GONNA CAUSE IT TO SPRING INTO ACTION.

AND THAT IS CALLED A TRIGGER.

Narrator: THEY ATTACK WHEN IT'S LEAST EXPECTED...

...AS ONE FAMILY IS ABOUT TO DISCOVER.

MAY 2002.

TONY AND VALERIE RICHARDSON

ARE A YOUNG COUPLE LIVING WITH THEIR TWO SONS,

4-YEAR-OLD ZACHARY AND 11-MONTH-OLD GARRETT.

ON THE SURFACE, THEIR LIFE SEEMS IDYLLIC.

WE FELT VERY LUCKY TO HAVE TWO GREAT KIDS.

[ LAUGHS ]

Tony: ONE OF OUR FAVORITE THINGS TO DO

IS TO GO OUT AND PLAY ON THE PLAY EQUIPMENT.

GARRETT LIKES TO SLIDE DOWN SLIDES,

AND HE LIKES PLAYING IN THE GRASS.

Narrator: BUT THEIR FAMILY IS ABOUT TO BE TORN APART.

GARRETT'S UNUSUALLY SLEEPY, AND HE'S TAKING EXTREMELY LONG NAPS,

AND WE WERE WORRIED

BECAUSE HE HAD NEVER SLEPT FOR THAT LONG BEFORE.

IT DIDN'T REALLY SEEM LIKE HE WAS SICK