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[BAND MUSIC PLAYING] NARRATOR: In 1985, 121 people in
South Dakota and Minnesota
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were struck with a mysterious
illness. There had been only one outbreak
like it.
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And the last time it happened,
medical detectives couldn't figure out the cause.
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[THEME MUSIC PLAYING] Valley Spring, South Dakota-- a
tiny farming community of about 800 people, not far
from the Minnesota border.
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It's a community of farms and
suburban professionals, many of whom work in the nearby
city of Sioux Falls.
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People here are accustomed to
hard work and the hard weather and aren't the type to complain.
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So when some residents began
suffering from irregular heart rhythms, fevers, weight loss,
diarrhea, edginess,
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and mysterious aches and pains,
they wondered if it was more than a
coincidence.
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RICHARD: I was just fidgety and
nervous. And uh-- not all the time. I guess that's what threw you
off.
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If it'd been a steady you, you
couldn't have put up with it. DANIEL: Heart was beating. You
know?
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You'd feel your pulse. And it was just pounding. You could feel your heart
pounding.
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And you hate-- your legs and
arms hurt real bad. JANE: I started getting chills.
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Then I'd get hot flashes. Then I couldn't eat. And I'd be nauseated. Everything was just happening
really, really fast.
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NARRATOR: At first, doctors were
confused about the symptoms. Jane Nettestad's doctor thought
she was having
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a nervous breakdown and put her
in the hospital. JANE: I'd never, you know, had
any of this problem
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before with the mental problems. So he put me on a mood elevator. And about eight hours later, my
heart was 160 beats per minute.
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And I just knew I was going to
have a heart attack. It felt like it was just flying
out of my chest.
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NARRATOR: 10 miles down the
road, in Luverne, Minnesota, the stories were the same.
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Tony Dispanet suffered heart
symptoms, too, and immediately went to the
emergency room
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certain he was having a heart
attack. NARRATOR: Well, about 3 o'clock
in the morning,
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uh, approximately 3:00, I woke
up with a, a tightness in my chest. Like some-- it did.
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It felt like somebody was
sitting on me. NARRATOR: Tests revealed it
wasn't a heart attack.
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But he spent three days in the
hospital as doctors tried to find out the
cause. Some of the local physicians
thought
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it was the flu or a virus. But after weeks of suffering,
the residents started to compare notes.
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RHONDA: There were folks that
were sick and had been sick for a long
time. And a couple were-- had gone
close to death.
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And they couldn't figure out
what was wrong with them. And they didn't know if it was
contagious,
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if it was something in the
water. -And they were all feeling these
same symptoms.
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And then they were hearing of
other people that were feeling these same
symptoms.
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NARRATOR: When Richard Jacobson
went to his doctor, he was told that his thyroid was
malfunctioning
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and was sent to the area's
leading thyroid specialist. When Jacobson called the
specialist,
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he had just one question. -Doc, can you tell me why
there's five people in my small town
with the same condition?
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NARRATOR: Doctor Michael
McMillin has been a thyroid specialist in
South Dakota for the past 30 years.
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At first, he thought Jacobson
was exaggerating. But just to make sure, he
decided
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to do a little of his own
investigating. He went to the local hospital
and looked through the x-rays
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and medical records of some
recent patients. He discovered something
alarming. There had been an increase in
the number of patients
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with thyroid type complaints. But there was a problem. Because in every x-ray, the
thyroids
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we're perfectly normal. The thyroid is a small
butterfly-shaped gland at the base of the neck, which
produces hormones that
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control both metabolism and
growth. An overactive thyroid floods the
body with hormones,
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disrupting the entire nervous
system, causing symptoms such as heart
fluctuations, weight loss,
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diarrhea, nervousness, muscle
aches and pains. Doctor McMillin searched the
medical journal for clues,
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trying to find out what could be
causing an outbreak of thyroid problems
in the area.
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DR. MCMILLIN: And I came across
a title that said, first ever epidemic of silent
thyroiditis, York, Nebraska.
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Well, York, Nebraska is about
120 miles south of here. NARRATOR: The outbreak in York,
Nebraska
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happened just one year earlier. Residents complained of the same
symptoms-- heart problems, fevers, fatigue,
loss of appetite,
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and weight loss. So many people were ill, it
threatened the economy of the small farming community.
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Doctors from the Centers for
Disease Control in Atlanta were called in to investigate.
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But just as they arrived, the
outbreak of silent thyroiditis ended as mysteriously as it had
begun.
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The residents recovered. And the cause of the York
outbreak was never discovered.
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Doctor McMillin immediately
called the CDC to let them know it was
happening again.
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-This is Dr. Michael McMillin
I'm trying to get a hold of Dr. Dan
Fishbein -I was-- knew that it was going
to happen again because I knew.
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The one thing we all admitted
is-- even the people who thought it was a virus-- we
didn't know what virus.
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We didn't know what it was
caused by. So I knew that was going to
happen again. And so I was not quite expecting
but certainly was not
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surprised. NARRATOR: As the CDC prepared to
investigate this outbreak, the number of cases was rising.
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-Even if it just spread to Sioux
Falls with all the people here, let alone Minneapolis or
Detroit or something,
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we would have a major medical
catastrophe on our hands. [CHEERING] NARRATOR: Investigators needed
to find
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the cause of the outbreak before
thousands were affected. In June of 1985, there were 50
cases of the mysterious thyroid
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outbreak concentrated in two
nearby towns, Luverne, Minnesota and Valley Springs,
South Dakota.
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The Centers for Disease Control
in Atlanta was called in to investigate. DR. FISHBEIN: Certainly on of
the most puzzling things
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about the outbreak is we didn't
know what it was due to. And this made it incredibly
difficult.
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Was it in the air? Was in the water? Was in the food? There, there was just no way to
know.
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NARRATOR: Investigators needed
to know as much about the outbreak as possible. It was striking both men and
women equally.
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All age groups were affected. There appeared to be no
occupation association and no worksite or school
clusters.
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Entire families were affected. Was it possible that the
outbreak was being spread person to
person?
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Everyone suspected of having the
disease was given a blood test and interviewed about where or
how
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they might have contracted it. DR. MCMILLIN: You talk to the
patients. And you hope that by doing
unstructured interviews,
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you'll get some ideas. One of the questions that I
thought was kind of cute that the
epidemiologist asked everybody
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was, what do you think causes
this? And the most frequent response--
there had been a lot of tornadoes in
this area the year before.
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The most frequent response was,
I guess those tornadoes stirred up some chemicals and that got,
that into our water supply.
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NARRATOR: But in order to
determine what was causing the outbreak, investigators
first
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had to figure out what the
problem was. Blood tests revealed that all of
the victims
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had an excess of thyroid hormone
in their system. In some cases, the levels were 8
and 10 times above normal.
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Tests of the drinking water did
not reveal anything which could have
caused the outbreak.
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Dr. Lewis Braverman is the
country's leading expert in thyroid
diseases. He was asked to examine some of
the sick patients
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in South Dakota. DR. BRAVERMAN: We then went out
to a small community called Beaver Creek if I recall.
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And went into one household
where there were four generations in the house
who had all of the signs
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and symptoms of thyrotoxicosis
And none of them, from a four-year-old child to an
85
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or 90-year-old great-grandfather
had an enlarged thyroid. NARRATOR: Since the thyroid
glands of these victims
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weren't enlarged, they had no
idea what was causing these symptoms. In the past, enlarged thyroid
glands
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were so common in this part of
the country it was known as "the goiter
belt." A goiter is the term for an
enlarged thyroid.
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-This part of the country's
called "the goiter belt" because there was iodine
deficiency here.
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There's no iodine in the soil. There's nobody eating seafood. And so people used to get large,
iodine-deficient goiters.
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NARRATOR: The condition was so
common, that in 1922, the Mayo brothers opened the Mayo Clinic
in nearby Rochester,
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Minnesota offering safe,
affordable surgery to alleviate the huge number of thyroid
problems in the region.
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Over the years, as diets
improved, the thyroid problems went away. But this outbreak was different.
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All of the patients had normal
thyroids. And for some patients, the
condition was serious.
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DR. MCMILLIN: One the cases was
a patient I had seen in the intensive care unit here
in the hospital.
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And it was an older lady who,
whose heart had suddenly started beating
irregularly.
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And she'd gone into heart
failure. NARRATOR: To find out if this
was indeed a virus,
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health officials decided to take
throat and fecal specimens for
analysis. But all of the tests were
negative.
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Then Dr. McMillin noticed
something interesting-- the geographic
location of many of the victims.
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DR. MCMILLIN: Here was a
community of Valley Springs. And then three miles across the
highway,
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was the community of Garretson,
which is almost the same size. There were nine people in Valley
Springs with the disease.
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Nobody in Garretson with the
disease. How could those two
communities-- what, what was,
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what was the difference? NARRATOR: In fact, the epicenter
of the outbreak was Luverne, Minnesota.
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And there were no cases west of
Valley Springs. But that changed. When a resident of Sioux Falls
call Doctor McMillin to say
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that she was suffering from the
thyroid disease. Her name, Rhonda Peskey. Her parents owned a grocery
store in Valley Springs
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where she occasionally purchased
her groceries. Dr. McMillin drove out to visit
her parents, Larry and Margaret
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Long, and to take a look around
their store. The Longs did not have
thyrotoxicosis,
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but their daughter did. Dr. McMillin wanted to know why. When Dr. McMillin learned that
the daughter of a grocery store
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owner developed thyrotoxicosis,
yet her parents did not, he decided to investigate.
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The grocery store owned by Larry
and Margaret Long had a specialty item, extra lean
ground beef.
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Dr. McMillin asked the Longs how
often they ate the ground beef
themselves. They laughed and said, never.
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It was such a popular item, they
were always sold out. -It was a great meat. It was, it was running about 90%
lean.
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NARRATOR: But the Longs said
their daughter might have taken some with her on her last visit.
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On a hunch, McMillin took a
sample for analysis. By now, there were more than 100
cases
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of the mysterious thyroid
outbreak. And for some, the symptoms were
troubling. -When I had that thyroid scan, a
couple
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gals that work in the hospital,
they thought I had cancer is what
they told me. They told me this personally
that we thought you were dying
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of cancer because I'd looked so
bad when I went in for this thyroid scan. -Then of course the world's
greatest
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endocrinologist were called in. And, and we had-- I remember the
meeting with them.
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And we'd laid out all the data,
told everything, and they sat there and shrugged
their shoulders and said,
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we don't know what this is. NARRATOR: The only thing they
knew was that patients had 8 or 10
times the normal amount
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of thyroid hormone in their
bloodstream causing heart problems, fatigue, muscle aches
and pain.
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Investigators finally got a
break when they heard of an entire
family with thyrotoxicosis.
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It was a large extended family,
all of whom had confirmed cases of the
thyroid condition, all except one.
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DR. FISHBEIN: It must have been
8 or 10 people. We bled everybody in the family.
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Did their blood test. And everybody had elevated
thyroid function tests except one
person.
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And that was a teenager. NARRATOR: But how was the
teenager different from the other family
members who got sick?
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The father told investigators he
worked at the local meat packing plant and regularly
brought
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ground beef home for his family. It was the same plant which
supplied the Long's grocery
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store with their specialty
hamburger, the extra lean ground beef. Samples of the hamburger were
collected for analysis
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and taken to a local
pathologist. Using a cryostat, a portion of
the hamburger was frozen in a matter of
seconds.
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DR. FISHBEIN: We convert the
tissue, really, into a block of ice. It makes the tissue firm enough
that we can cut thin sections,
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stain them, look at them under
the microscope, and make a diagnosis. NARRATOR: Under a microscope,
the pathologist
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noticed something unusual,
something not normally seen in ground beef-- bits of animal
thyroid
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mixed into the ground meat. Animal thyroid contains
extremely high levels of thyroid hormones.
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Was it possible that this was
causing the outbreak of thyrotoxicosis in the two
small communities?
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To find out, doctors conducted
an experiment. DR. BRAVERMAN: One can say,
well, just because you find it
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in the hamburger, how do you
know that when the people eat the hamburger that they're
really
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absorbing the thyroid hormones? So our next step was to feed the
ground beef from Minnesota to rats.
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NARRATOR: One group of rats were
fed the raw hamburger collected in
Minnesota. And for comparison, another
group
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was fed raw burger purchased
near the laboratory in Worcester, Massachusetts. The rats which ate the Minnesota
burger
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exhibited all the signs of
thyroid problems. DR. BRAVERMAN: These rats were
wild rats.
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I mean, they were very jittery,
nervous. And this is compared to the
rather tranquil,
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normal behavior of the rats fed
the Worcester hamburger. So that there's no question that
these rats were-- one
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could use the expression
clinically thyrotoxic. NARRATOR: But residents of
Valley Springs and Luverne
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weren't eating raw hamburger. And cooking the meat usually
kills all bacteria and microorganisms.
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DR. BRAVERMAN: Most of us eat
cooked hamburger. And as a matter of fact, people
in the Midwest
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tend to cook their hamburgers
much more so than we do in the Northeast. NARRATOR: Investigators' next
step,
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to do some tests on humans. They also wanted to know how an
entire family developed
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thyrotoxicosis while their young
son did not. When investigators from the CDC
found a large extended family
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who all suffered from thyroid
problems, except their young son, they
wanted to know why.
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Interviews with the family
revealed that the boy didn't eat meat except for an
occasional pepperoni pizza.
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-I hate meat. I like this. -Oh. And he's my son. NARRATOR: This was an important
discovery.
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The next step, to confirm that
the tainted hamburger create elevated thyroid hormone levels
in humans
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as it did with the rats even
after it was cooked. DR. BRAVERMAN: So that we did
obtain for young physicians
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to participate in the study. And what we did was essentially
bring them in the morning,
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fasting, drew their blood, and
fed them an extremely well cooked half pound hamburger,
which they enjoyed immensely
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since the-- it was smothered in
onions and on toast. So it was a very tasty
breakfast.
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NARRATOR: The meat used in the
experiment was the same that was sold in the local
stores.
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It came from this local
slaughtering house in Luverne, Minnesota. But how was the local meat being
contaminated?
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Public health officials
inspected the local meatpacking plant and learned something
interesting.
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The plant had been a kosher
killing plant up until a few years
earlier. -When animals are killed kosher,
they're actually bled to death.
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And the thyroid gland, it has a
real intense blood supply. And it's really red. Except that if you bled the
animal death,
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then it would look white. And it would look completely
different. NARRATOR: And when the thyroid
gland changed color,
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it was easier for the butcher to
see and remove. The animal thyroid was then sold
to drug companies.
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-All the meat packing companies
would carefully dissect the thyroids out and
sell them to the drug
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companies, so they could make
thyroid extract to treat other people. NARRATOR: But two things
happened.
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First this meat plant
discontinued its kosher killing production. And with the development of
synthetic hormones,
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drug companies no longer
purchased the animal thyroids from slaughter houses. The result-- since the animal
thyroid
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wasn't sold to the drug
companies, it was included along with the
rest of the neck
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trim from the animals' gullet
and inadvertently passed along for human
consumption.
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-The gullet basically is this
part of the cow's neck. And the muscles that are trim,
that are low fat,
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are these muscles here. They're the sternocleidomastoid
muscles in humans. The thyroid gland sits right
under those muscles.
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And if someone is not paying
attention as they're trimming, it's very easy to clip off a bit
of thyroid gland
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as they take off the muscle. NARRATOR: When the animal's
thyroid gland was a mixed in with others
ground meat for hamburger,
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it caused the highly elevated
levels of thyroid hormones in those who ate it. The meat plant was producing the
equivalent
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of 3,600 hamburger patties each
day. But as soon as the problem was
discovered, they immediately recalled the
beef
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and instituted safeguards to
prevent the problem from recurring. -Well, it was almost like the
eureka type thing.
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We were-- we were really quite
thrilled. We thought that we had, at that
point in time,
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discovered the cause of this
epidemic. And it was something relatively
simple. NARRATOR: A simple solution to a
complicated problem.
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After seven months of
investigation, the cause of the outbreak was
finally discovered.
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And investigators believe that
the tainted meat also was the cause of the outbreak in
York, Nebraska the year before.
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Shortly after this outbreak, the
US Department of Agriculture instituted strict guidelines for
the trimming of meat
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from neck muscles and declared
the thyroid gland was to be considered unfit for human
consumption.
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But the residents of Valley
Springs and Luverne don't care much about their
place in medical history.
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And they aren't the type to hold
a grudge. 121 residents developed
thyrotoxicosis.
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And all recovered. Fortunately, there were no
fatalities. -It's become one CDC's major
teaching cases because it
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illustrates all sorts of things
that are really not usually encountered but are very
important
00:21:51
lessons for young
epidemiologists. NARRATOR: The outbreak was
halted promptly thanks
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to skill, intuition, a little
bit of luck. All are important ingredients in
a successful medical
investigation.
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[THEME MUSIC PLAYING]