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We Thought Cancer Was Uncontagious. We Were Wrong.
We Thought Cancer Was Uncontagious. We Were Wrong.
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Phụ đề (201)
0:00
Cancer is one of the most terrifying diseases on Earth.
0:03
It is unpredictable and often impossible to cure, only controlled. But there has always
0:07
been one comfort, you can’t catch it. It comes from your own cells going rogue.
0:13
At least… that’s what we thought. That all changed in 2013. A man was
0:16
being eaten alive by aggressive tumors… that belonged to a different species entirely.
0:21
What doctors discovered next would force them to question everything they knew about the disease.
0:26
In January 2013, a man was rushed to a busy hospital in Medellín, Colombia. He was in
0:31
bad shape, suffering from rapid weight loss, a persistent fever, and a medical history of
0:36
HIV. It had been manageable with medication, but he had stopped taking it a few months earlier.
0:41
Any one of these factors could have caused a health emergency, or all of them combined.
0:45
HIV is not uncommon in Colombia, and unlike in many countries, the combination of poverty and
0:50
poorer medical infrastructure means fewer people keep up with the health and medication regimen
0:54
needed to survive it long-term. The initial symptoms of fatigue, a cough, and weight loss
1:00
were compatible with this diagnosis, but the swelling was an unusual side effect.
1:04
And even more shocked when they looked closer.
1:07
It was clear the man was seriously ill, so a battery of tests was administered.
1:11
The man’s HIV status revealed that his viral load had skyrocketed. Stool samples were taken,
1:16
and revealed a tapeworm infestation in his digestive tract. Specifically,
1:20
it was Hymenolepis Nana, the dwarf tapeworm, a common species in humans, especially in
1:26
temperate zones. But the most concerning part of the man’s condition showed up on x-rays.
1:31
He was riddled with tumors all through his body.
1:34
The man’s breathing was highly labored, which didn’t conform with other causes for
1:38
his condition. X-rays of his lungs and lymph nodes revealed that the apparent cancer was
1:42
concentrated there. While some tumors are benign and can be safely removed,
1:46
an abundance like this usually means malignant cancer, and biopsies were quickly taken. Upon
1:51
examining the cancer cells under a microscope, the case continued to become more and more bizarre.
1:57
The cells didn’t resemble standard cancer cells at all.
2:00
In fact, they didn’t seem to be human. The man quickly deteriorated. The strange
2:04
foreign cells had caused golf ball-sized tumors in his lymph nodes, making it difficult for him
2:09
to even turn his head. His breathing became more and more labored. The standard treatment
2:13
for acute cancer, chemotherapy, wasn’t going to be of any use here. Mainly because no one
2:19
knew how the chemical cocktail would work against a parasitic infestation.
2:22
But his legacy as one of the strangest medical case studies in history was just beginning.
2:27
A true medical mystery is unusual in a hospital. To those trying to save a life, it can be a
2:33
nightmare. To pathologists, it can be a dream come true. And as soon as the more powerful microscopes
2:38
were called into service, it became clear this was not a case that would be solved in the
2:42
hospital. The biopsy was one of the most baffling results anyone at the hospital had ever seen.
2:47
These tiny cells were up to 10 times smaller than a standard cancer cell,
2:51
creating a scan that was confusing at best. The hospital had sent the scans out to pathologists
2:56
in hospitals and research centers they were in contact with. One of those scientists was Dr.
3:01
Atis Muehlenbachs, a researcher and pathologist at the Centers for Disease Control and Prevention.
3:06
Even for Muehlenbachs, this was a bizarre sight.
3:09
The samples from the biopsy didn’t match any condition he had ever seen. They looked like
3:13
sheets and clumps of tightly clustered cells that behaved completely differently from human cancer
3:18
cells. In fact, at first he thought it was a slime mold. There was only one thing that was clear,
3:23
the cells were on the move. Like other cancer cells, they were reproducing, fast. They were
3:28
also crowding out their competitors in an even more life-threatening way than human cancer cells.
3:33
To Muehlenbachs, this was potentially an existential threat.
3:36
In Colombia, the man continued to linger in the hospital, his condition a mystery. With
3:40
his apparent cancer not matching any medical records, the hospital was left to focus on
3:44
palliative care. It would be over 2 months before the first breakthrough in the case.
3:49
The CDC ran broad-range PCR testing on samples taken from the Colombian hospital,
3:54
screening for genetic material across a wide range of possible causes. But
3:58
when the DNA from the tumor tissue finally came back, it didn’t match anything human.
4:03
Yes, the man had cancer… but it wasn’t his cancer.
4:06
It was from the tapeworm infestation inside him.
4:10
For the first time, a foreign entity had managed to seemingly transmit cancer to a human being,
4:15
creating a new and bizarre disease. That result changed the entire direction of the investigation,
4:20
turning a routine search for disease into something far more unsettling.
4:24
In 2013, Colombian doctors tried to diagnose him with small-cell lung cancer. Sure, the cells were
4:30
smaller than the average, but it was close enough. By the time the diagnosis was first unlocked and
4:34
the tapeworm DNA was identified, it was already too late. The man’s condition had gone seriously
4:40
downhill, as the cancer had spread through his body. He was bedbound, barely able to breathe,
4:45
and after 72 hours he passed away before a treatment plan could even be conceived.
4:49
But the mystery would linger on.
4:51
It would outlast the man by nearly 300 times his remaining lifespan. He lived
4:56
only 3 more days after the diagnosis, but it took scientists 2 and a half years to
5:00
complete the full genetic sequencing needed to map the tapeworm’s cancer mutations.
5:05
Over the course of those two years, several different tests came back positive for human DNA,
5:10
but they were all faulty. The tapeworm cells came just close
5:13
enough to small-cell lung cancer that the false results were passed on multiple times.
5:18
Scientists missed the clues that were right in front of them.
5:21
Because while doctors and researchers were looking
5:22
at the man’s lungs, the real horror was happening inside his intestines.
5:27
The tapeworm is one of the most disgusting creatures alive. It infests the digestive
5:31
tract of a person, feeding off the same nutrients they eat and growing. This has
5:36
led it to develop a morbid fanbase as a weight-loss tool. Of course,
5:40
unlike diet and exercise, the tapeworm is actively dangerous to its hosts.
5:44
Most tapeworms reproduce through human waste. Tapeworm eggs wind up in feces,
5:49
which enters the sewage system, and the eggs get eaten by other animals. The tapeworm larvae
5:54
hatch in these intermediate hosts, before finding new human hosts for the long adult
5:59
life cycle. It’s a disgusting life cycle - but a manageable one for most people.
6:03
Except for one species.
6:05
The dwarf tapeworm.
6:06
It really exceeds 1.5 inches (40 millimeters) long and 0.04 inches wide (1 millimeter)wide. That
6:12
makes it much harder to detect… and much harder to get rid of. Like other tapeworms,
6:16
it attaches itself to the lining of the digestive tract using hooks and suckers.
6:20
It enters the human body through contact with its eggs, often spread through contaminated
6:25
food. But what it does once inside is what makes it far more dangerous than expected.
6:31
It keeps going.
6:32
Inside a hospitable host, the eggs can be laid, hatch, and start the cycle anew. It’s
6:37
uncommon for a single person to have more than one of another species of tapeworm,
6:41
which allows the parasite to grow to disturbing lengths in some cases. But it’s far more dangerous
6:46
when they do have competition, because a dwarf tapeworm population can grow out of
6:51
control if it’s not treated. That’s when it starts having serious impacts on the
6:55
functioning of the body, leading to rapid weight loss as the population skyrockets.
7:00
Like any cell, tapeworm cells can mutate when they reproduce. There’s always the
7:04
risk for cancer in any organism. But when a smaller organism develops cancer, it’s
7:08
much less likely to be noticed by humans and the infected specimen is likely to die off quickly.
7:14
But his time was, the environment was a little too hospitable.
7:17
Due to lack of treatment and access to resources, the man who showed up at that Medellin hospital
7:22
in 2013 had allowed a colony of tapeworms to develop inside his gut. At some point,
7:27
one of them developed cancer, and before it could die, its mutated cells were transferred into him.
7:32
The parasite was effectively growing its own tumors while living inside another organism, and
7:38
those tumors were reproducing alongside it. Over time, something even stranger appeared to happen.
7:43
The cancer seemed to realize that the host
7:45
might make a better place for the tumors than the tapeworm.
7:48
And so began one of the most disgusting jailbreaks in medical history.
7:52
But how did the cancer-riddled cells of a foreign organism survive the human immune system?
7:57
The fact is, we all have parasites. At any given moment, the human body is home to billions of
8:02
microscopic organisms that perform a mutualistic role. While there is no average estimate,
8:07
worms in the digestive tract and mites on the skin and hair are incredibly common. In most cases,
8:12
they either quietly coexist in the body without causing harmful effects,
8:16
or are eventually killed off by the human immune system.
8:19
But this wasn’t the average person.
8:21
The tapeworms and their cancer was what eventually killed the man in Medellin,
8:25
but his fate had been written long before that. At the root of his illness was his HIV positive
8:30
status. In the modern day, many people with HIV live completely normal lives save for a regular
8:36
medication regimen. This allows them to maintain their regimen getting to “undetectable” status,
8:41
where the viral load can’t be passed on to lovers or future children.
8:44
But if that regimen is dropped, things go wrong fast.
8:48
In the past, HIV was a death sentence because it led to AIDS which ripped its way through the
8:53
human immune system, killing off resistance to common illness. Very few people who died
8:57
of the AIDS epidemic were killed off by the virus itself. They died of common respiratory ailments
9:02
or infections that a healthy person could have fended off. The virus damages the CD4 cell count,
9:08
also known as white blood cells. Tests showed that the patient’s
9:12
white blood cell count was only around 2% of the amount that a healthy person would have.
9:16
An army that goes to war with 2% of its men is going to get slaughtered.
9:21
An untreated tapeworm infestation in a healthy person would be noticeable
9:25
quickly due to the weight loss. But it would be likely to stay in the digestive
9:29
system. That’s not what happened here. With the natural human defenses so weak,
9:33
the tapeworm’s mutant cells were able to infest the walls of the intestines
9:36
themselves. From there, they started flowing smoothly through the bloodstream. Soon,
9:41
they were in his lymph nodes and his lungs, reproducing. While the species of tapeworm
9:45
itself was still confined to his digestive tract, the mutant cells had found a new home.
9:50
One that was incompatible with the host’s continued survival.
9:54
And the tragic part is, all of this was avoidable.
9:57
It’s easy to assume that HIV has been, if not cured,
10:00
managed. For most people in the United States, Europe, their HIV medications are
10:05
covered by their insurance and can get on with their lives with careful maintenance.
10:09
But around the world, approximately 630,000 people die of AIDS every year.
10:13
In some countries, there simply isn’t the infrastructure to ensure proper health care,
10:17
with many relying on programs like US Aid to make access possible. In others,
10:22
those with HIV are afraid to come forward. But the largest cause of this death cycle is simply,
10:27
poverty. Many people in countries like Colombia can’t afford the drugs if they’re
10:31
not properly covered. While we’ll never know if this was the case for the victim,
10:36
the lack of maintenance of his anti-HIV regimen opened his body up to the infestation.
10:40
But that could have been prevented too.
10:43
Tragically, there’s a drug named Praziquantel which is used to treat a wide array of parasitic
10:47
worm infections. It’s used to clear up infections in pets, but can be used to cure humans as well.
10:54
It is commonly prescribed for treating tapeworm infections, but obtaining it still requires
10:58
both awareness of the condition and access to medication. In this case, the man had neither.
11:02
The drug typically costs between 7 and 20 cents in many developing countries, making it one of
11:07
the most affordable treatments available. But it was still out of reach when it mattered most.
11:12
In this case, a tragic series of misunderstandings doomed the patient.
11:16
No one knows if the man was too far gone to be saved when he came in. His viral
11:19
load due to his HIV was spiking, and it may have been too long without treatment
11:24
to turn it back effectively. But the tapeworm infestation that
11:27
ultimately led to his death could have been had for less than a single bottle of water.
11:31
If this man lived in a country with a lower poverty rate and a more stable health care system,
11:35
he likely would have been saved long before things reached this point. He would have been
11:39
under the care of a physician monitoring his HIV treatments, who would have reached out to
11:43
him long before he went without pills for months. Once he came in with this tapeworm
11:47
infection that had turned into a foreign cancer, access to world-class pathologists meant nothing.
11:53
No hospital in the world could have diagnosed it earlier, not without specialized help.
11:57
Something like this had never happened before.
12:00
And the scariest thing is, this is going to happen again.
12:03
When people read the bizarre case study of the man who got infected with tapeworm cancer,
12:07
the question on many of their minds was “Could it happen to me?”.
12:11
The answer is no…but also yes.
12:14
The horrors that befell this man were a mix of failures on many different levels. His health
12:18
had been allowed to deteriorate to the point that the infection raged out of control. Then,
12:22
his hospital lacked the resources to diagnose and treat him quickly,
12:26
and the distance and lack of hands-on access hampered the CDC’s efforts in diagnosing him.
12:30
H. Nana is one of the most common parasites around the world, infecting up to 75 million
12:36
people around the world each year. For many of them, it’ll be little more than an annoying
12:40
infection cleared up with a regimen of pills. For others, who don’t have access to that,
12:44
it’ll be a persistent sickness that may shorten their lives. But the pool of 75
12:49
million, roughly the equivalent of the combined population of the United Kingdom and Ireland,
12:53
is likely to have a large number of people with HIV in it, especially in developing countries.
12:59
Now every one of them could be vulnerable.
13:01
With what is known now, the case of the man with tapeworm cancer was not the beginning of a new
13:06
kind of parasitic epidemic or a freak mutation taking over the species. Instead, the parasite
13:11
was doing exactly what it always does: feeding, growing, mutating, and reproducing. The difference
13:16
was the environment inside the host, which allowed those processes to spiral unchecked. The outcome
13:21
was rare, disturbing, and fatal for one man, but it also raised a broader concern: under
13:26
the right conditions, similar vulnerabilities could exist in other patients around the world.
13:31
The worst-case scenario that many feared when news of this strange case broke hasn’t come to pass,
13:36
thankfully. There is no new form of cancer that has jumped from tapeworm to human.
13:41
Instead, what we’ve discovered is a disturbing new vulnerability in our
13:44
own body. If our natural defenses get low enough, we become vulnerable not
13:48
just to our own cells turning on us … but to parasites infecting us with their own.
13:53
And that means we might have to rethink what cancer actually is.
13:57
For the first time, we’ve seen a foreign cell grow in a person, use their blood and biome to grow,
14:02
and eventually kill the host. This wasn’t a planned parasitic infestation,
14:06
it was the equivalent of someone going to an all-you-can-eat buffet and eating themselves
14:10
sick. The man was especially vulnerable, and the mutated tapeworm cells were especially voracious.
14:16
But if it can happen once, it can happen again - and pathologists everywhere will be looking at
14:21
every biopsy a little more carefully, just in case it’s not a human disease they’re dealing with.
14:26
This isn’t the only medical horror story involving a parasite. Some take over completely.
14:31
Watch Most Painful Parasites That Infect Humans to get the gory details. Or click on this video.
