Parasites Eating Us Alive

00:45:39
https://www.youtube.com/watch?v=YAqcQ_Ycro4

الملخص

TLDRThe video provides a detailed overview of the impact of parasitic infections on human health, noting that billions are affected globally by various forms of parasites. It highlights the 1993 Milwaukee outbreak of cryptosporidium, revealing how contaminated water can lead to a public health crisis. The film explores different types of parasites, including malaria, schistosomiasis, and hookworms, discussing their transmission methods, symptoms, and the challenges in developing treatments or vaccines. The evolution of these parasites poses ongoing difficulties for public health efforts, necessitating innovative research and preventive measures to control and reduce infections.

الوجبات الجاهزة

  • 🌍 Three and a half billion people are infected with parasitic worms.
  • ⏳ Malaria kills a child every 30 seconds globally.
  • 🚰 The Milwaukee outbreak was caused by water contamination.
  • 🦟 Malaria is transmitted through Anopheles mosquitoes.
  • 🔬 Parasites are evolving and challenging treatment methods.
  • 💧 Clean water is crucial to prevent parasitic infections.
  • 🌡️ Vaccination against parasites remains a significant challenge.
  • ❤️ Humanitarian motives drive research in parasitology.
  • 📉 Malaria significantly impacts economic productivity in affected regions.
  • 💡 Innovative control programs have shown success in reducing infections.

الجدول الزمني

  • 00:00:00 - 00:05:00

    The documentary highlights the global scale of parasitic infections, affecting billions of people and leading to severe health issues such as malformations, blindness, and death. Parasitic diseases, particularly malaria, are depicted as significant threats to public health around the world, with rates of infection staggering and often going untreated due to their complexity.

  • 00:05:00 - 00:10:00

    In April 1993, Milwaukee faced a terrifying outbreak of cryptosporidiosis, urging health authorities to rapidly seek answers as hundreds of thousands became infected. The city’s water system was discovered to be contaminated, demonstrating the ease with which parasites can spread through water, leading to widespread illness and panic.

  • 00:10:00 - 00:15:00

    The outbreak exposed the unexpected vulnerability of the municipal water supply to parasites, with cryptosporidium identified as the main culprit. This outbreak resulted in a significant number of illnesses and ultimately, deaths, particularly among individuals with weakened immune systems.

  • 00:15:00 - 00:20:00

    Parasitic organisms are defined, highlighting their often harmful presence in hosts, with humans being common victims. The documentary identifies how nearly all humans harbor some form of parasites, and notes their historical persistence in human evolution.

  • 00:20:00 - 00:25:00

    The documentary explains the nature of parasitic infections and differentiates between types, focusing on single-celled organisms and multicellular worms. It emphasizes the evolutionary skill of parasites to invade hosts, adapt, and elude medical treatments, showcasing their complex life cycles and survival mechanisms.

  • 00:25:00 - 00:30:00

    The transmission of parasites to humans is discussed, primarily through ingestion or bites from arthropods. The risk posed by vectors is underscored, especially in tropical regions, where these organisms thrive and often lead to debilitating diseases such as lymphatic filariasis and schistosomiasis.

  • 00:30:00 - 00:35:00

    Imported foods and contaminated drinking water increase exposure to parasites, including sushi-borne anasakis. The documentary highlights both the human and environmental risks parasites pose in modern-day societies and emphasizes the existing challenge in combating foodborne infections.

  • 00:35:00 - 00:40:00

    The impact of malarial infections is examined through personal stories, illustrating the real consequences of malaria on human lives, particularly on children. Despite medical advances, malaria remains a major killer globally, with many failing to recover once severely infected due to the parasite's virulence and the immune response triggered within the host.

  • 00:40:00 - 00:45:39

    While some approaches have succeeded in controlling certain parasitic infections, eradication remains elusive. The documentary showcases examples of control efforts like the oncochiasis control program and highlights the ongoing need for research, surveillance, and innovative strategies to manage and treat parasitic diseases effectively.

اعرض المزيد

الخريطة الذهنية

فيديو أسئلة وأجوبة

  • What is the estimated number of people infected with parasitic worms globally?

    Three and a half billion people worldwide are infected with parasitic worms.

  • How often does malaria kill a child?

    Malaria kills a child every 30 seconds.

  • What was the cause of the Milwaukee outbreak in 1993?

    The Milwaukee outbreak in 1993 was caused by the cryptosporidium parasite that contaminated the city's water supply.

  • What is the primary method of transmission for malaria?

    Malaria is primarily transmitted by the bite of infected female Anopheles mosquitoes.

  • What complex issues are associated with parasitic infections?

    Parasitic infections present complexities like evolving resistance against treatments, difficulty in vaccination development, and challenges in water safety.

  • What are some examples of ectoparasites?

    Examples of ectoparasites include mosquitoes, fleas, head lice, and pubic lice.

  • How do parasites invade the human body?

    Parasites invade the human body typically through ingestion of contaminated food or water, sexual intercourse, or bites from arthropod vectors.

  • What is one successful program mentioned for controlling parasitic infections?

    The oncochiasis control program is mentioned as a successful initiative that protected the vision of over 600,000 Africans.

  • Are there any effective vaccines for malaria?

    Research is ongoing, but no practical vaccine against malaria currently exists.

  • What motivates researchers in the field of parasitology?

    Researchers in parasitology are often motivated by humanitarian goals to better the world and control parasitic spread.

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الترجمات
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التمرير التلقائي:
  • 00:00:07
    three and a half billion people
  • 00:00:09
    worldwide are infected with parasitic
  • 00:00:11
    worms
  • 00:00:13
    malaria kills a child every 30 seconds
  • 00:00:18
    entire african villages are taken down
  • 00:00:20
    by predatory parasites
  • 00:00:22
    that leave villagers grossly deformed
  • 00:00:25
    blind
  • 00:00:26
    or dead deadly waterborne illness
  • 00:00:30
    infested fruits and vegetables and
  • 00:00:32
    debilitating lyme disease threaten
  • 00:00:35
    communities throughout america
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    every day hookworm sucked the blood of
  • 00:00:41
    1.5 million people
  • 00:00:44
    [Music]
  • 00:00:45
    parasites voracious animals that live
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    off the very essence of our being
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    thriving since the dawn of man so
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    complex no vaccine will touch them
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    parasites are evolving they appear to be
  • 00:01:02
    indomitable and they are
  • 00:01:05
    eating us alive
  • 00:01:17
    april 1993 a strange illness creeped
  • 00:01:21
    across milwaukee
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    personnel called in sick to hospitals
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    and businesses
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    school classrooms stood eerily empty
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    paul nanas
  • 00:01:31
    was head of wisconsin's health
  • 00:01:32
    department as the numbers grew
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    from see there were 100 people that
  • 00:01:37
    presented to the emergency rooms to
  • 00:01:39
    several hundred people
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    to now a thousand people obviously by
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    then we knew there was something
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    significant going on
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    for five days doctors scientists and
  • 00:01:49
    administrators
  • 00:01:50
    desperately looked for answers while
  • 00:01:53
    hundreds of thousands of the city's
  • 00:01:54
    residents were writhing
  • 00:01:56
    wretching and rapidly wasting away
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    if it was a contained neighborhood
  • 00:02:02
    likely to be food
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    if it was uniformly dispersed across the
  • 00:02:06
    city given wind patterns it would be air
  • 00:02:08
    but what began to emerge was a pattern
  • 00:02:10
    of illness that kind of mirrored
  • 00:02:13
    the water distribution in milwaukee
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    the pressure mounted from a terrified
  • 00:02:19
    public in a frenzied media
  • 00:02:21
    the city's water system was infested
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    but with what finally one doctor on
  • 00:02:27
    milwaukee's east side
  • 00:02:29
    remembered his medical school training
  • 00:02:30
    in tropical disease
  • 00:02:32
    he checked his patients for parasites
  • 00:02:35
    the lab tests came back
  • 00:02:36
    positive cryptosporidium
  • 00:02:39
    a tiny one-celled parasite had lodged
  • 00:02:42
    itself in the intestines of 400
  • 00:02:44
    000 of this city's residents and even
  • 00:02:47
    when we learned that it was
  • 00:02:48
    cryptosporidium
  • 00:02:50
    we still didn't know what the source was
  • 00:02:52
    and whether our current water was
  • 00:02:54
    currently infected
  • 00:02:55
    and until we knew that we only knew part
  • 00:02:57
    of the equation
  • 00:02:59
    they had their culprit but the scare was
  • 00:03:02
    just beginning
  • 00:03:04
    paul nanus and the city of milwaukee
  • 00:03:06
    were in the midst of the largest
  • 00:03:08
    parasitic outbreak ever recorded in the
  • 00:03:10
    united states
  • 00:03:13
    nausea cramping some vomiting but
  • 00:03:16
    particularly diarrhea and the diarrhea
  • 00:03:19
    in this instance the diarrheal disease
  • 00:03:21
    was terribly severe
  • 00:03:23
    there were people that had 20 and 25
  • 00:03:25
    episodes
  • 00:03:27
    of diarrhea in a day i mean they just
  • 00:03:30
    couldn't
  • 00:03:31
    get out of their homes they had to stay
  • 00:03:33
    home
  • 00:03:34
    nobody ever believed i mean even when we
  • 00:03:37
    knew
  • 00:03:37
    it was waterborne we identified the
  • 00:03:40
    source we knew what it was
  • 00:03:42
    there was still this almost incredulous
  • 00:03:45
    kind of reactions that how could our
  • 00:03:47
    water
  • 00:03:48
    be the source of this i mean nobody
  • 00:03:50
    believed that it could be water
  • 00:03:53
    the shock deepened at the news of the
  • 00:03:55
    first death
  • 00:03:56
    then another by the time the epidemic
  • 00:03:59
    played itself out
  • 00:04:00
    200 people were dead from complications
  • 00:04:03
    from the cryptosporidium parasite
  • 00:04:08
    it was difficult for healthy people to
  • 00:04:10
    recover
  • 00:04:11
    from the episode so you can understand
  • 00:04:15
    what happened to people that didn't have
  • 00:04:16
    healthy immune systems they just
  • 00:04:18
    couldn't
  • 00:04:19
    shed it those who died had compromised
  • 00:04:22
    immune systems
  • 00:04:23
    people with hiv people already sick the
  • 00:04:26
    very old
  • 00:04:27
    and the very young that first three
  • 00:04:29
    weeks of it
  • 00:04:31
    were incredibly intense media wise the
  • 00:04:33
    public the aids
  • 00:04:35
    activist community that were marching
  • 00:04:37
    down through the city of milwaukee
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    wanting to know why people that they
  • 00:04:42
    knew and cared about were dying and what
  • 00:04:43
    were we doing about it
  • 00:04:45
    as i mentioned here we didn't have
  • 00:04:46
    answers that's a terrible feeling
  • 00:04:52
    parasitism is kind of a lifestyle
  • 00:04:55
    and uh and a parasite is an organism
  • 00:04:58
    that
  • 00:04:59
    lives on or in another organism which we
  • 00:05:03
    refer to as the host
  • 00:05:05
    and does so either at the detriment of
  • 00:05:09
    the host or
  • 00:05:10
    certainly at no benefit of the host so
  • 00:05:12
    you can have some parasites that really
  • 00:05:14
    don't cause a lot of harm
  • 00:05:16
    but they certainly aren't beneficial to
  • 00:05:18
    the host there are many parasites that
  • 00:05:19
    actually cause
  • 00:05:21
    great harm and in fact can kill the host
  • 00:05:25
    when you look at the human condition and
  • 00:05:27
    you say what is a human being
  • 00:05:29
    you could redefine what a human being is
  • 00:05:31
    in terms of its
  • 00:05:32
    ability to harbor parasites
  • 00:05:36
    almost all of our internal organs all of
  • 00:05:39
    our blood spaces
  • 00:05:40
    all of our hollow organs offers
  • 00:05:43
    opportunities for organisms to live in
  • 00:05:45
    them
  • 00:05:46
    and when they do and when they cause us
  • 00:05:48
    harm
  • 00:05:49
    we call those parasites parasites are
  • 00:05:52
    probably the most common agents
  • 00:05:54
    of human disease on our planet i often
  • 00:05:57
    like to say that if
  • 00:05:58
    carl sagan did not go into astrophysics
  • 00:06:01
    but instead chose to
  • 00:06:02
    launch a career in medicine or
  • 00:06:04
    biological sciences he would have had to
  • 00:06:06
    become a parasitologist
  • 00:06:08
    why because this is the only group of
  • 00:06:11
    organisms where we can really talk about
  • 00:06:13
    billions
  • 00:06:14
    and billions of people being infected
  • 00:06:18
    parasites tenacious behavior toward
  • 00:06:20
    their human hosts
  • 00:06:21
    is nothing new they have been at work
  • 00:06:24
    since the beginning of life
  • 00:06:26
    itself and no matter what form of life
  • 00:06:29
    has
  • 00:06:30
    existed on earth there has always been
  • 00:06:32
    parasites
  • 00:06:34
    always that's the nature of things so
  • 00:06:36
    from the very beginning
  • 00:06:38
    we assume parasitism parasites are very
  • 00:06:41
    clever though
  • 00:06:42
    in the way that they've evolved over
  • 00:06:44
    time and the mechanisms they've evolved
  • 00:06:46
    to
  • 00:06:47
    infect new hosts or move into new areas
  • 00:06:49
    where they previously haven't been
  • 00:06:52
    just the the sheer complexity of some of
  • 00:06:54
    the life cycles
  • 00:06:55
    that they've developed or have developed
  • 00:06:57
    over time in their association with
  • 00:06:59
    animals
  • 00:07:00
    it's just amazing as life progresses and
  • 00:07:03
    becomes more complex
  • 00:07:04
    and develops defense mechanisms against
  • 00:07:07
    those parasites
  • 00:07:08
    and excludes the common ones it now
  • 00:07:11
    has to put up with the highly evolved
  • 00:07:13
    parasites which have
  • 00:07:14
    also evolved along with those highly
  • 00:07:17
    evolved defense mechanisms
  • 00:07:19
    for stealth and entry mechanisms and
  • 00:07:21
    cunning and
  • 00:07:22
    guile so to speak we would give them
  • 00:07:24
    human characteristics
  • 00:07:27
    in fact in their own way the physical
  • 00:07:30
    structure of parasites
  • 00:07:32
    resembles that of our own they have
  • 00:07:35
    a complexity of structure and function
  • 00:07:38
    that is hard to believe
  • 00:07:42
    most of the parasites i work with have
  • 00:07:44
    structures that are just like man they
  • 00:07:45
    have
  • 00:07:46
    intestinal systems they have their own
  • 00:07:49
    kidneys they have a complex nervous
  • 00:07:51
    system
  • 00:07:53
    organisms such as bacteria and viruses
  • 00:07:56
    also require nourishment and protection
  • 00:07:59
    from a host
  • 00:08:00
    for survival the difference between
  • 00:08:02
    these microbiological organisms
  • 00:08:05
    and the classic parasite comes down to
  • 00:08:08
    size
  • 00:08:09
    usually when we talk about parasites we
  • 00:08:11
    talk about either single-celled or
  • 00:08:13
    larger organisms
  • 00:08:15
    we don't talk about smaller
  • 00:08:18
    organisms such as viruses for sure
  • 00:08:22
    and usually bacteria bacteria are
  • 00:08:24
    usually considered
  • 00:08:25
    kind of as a separate grouping
  • 00:08:29
    scientists group parasites into three
  • 00:08:32
    different categories
  • 00:08:35
    parasitologists will think about the
  • 00:08:38
    organisms that they study the parasites
  • 00:08:41
    along three major lines these would
  • 00:08:44
    include
  • 00:08:45
    simple single celled organisms
  • 00:08:48
    classically protozoan organisms
  • 00:08:51
    such as organisms that cause african
  • 00:08:53
    sleeping sickness
  • 00:08:55
    plasmodium which causes malaria
  • 00:08:57
    cryptosporidium which causes
  • 00:08:59
    cryptosporidiosis
  • 00:09:00
    which even despite their tiny size can
  • 00:09:03
    still be associated with devastating
  • 00:09:05
    disease
  • 00:09:06
    then there are larger multicellular
  • 00:09:09
    organisms generally referred to as
  • 00:09:11
    worms three different kinds of worms
  • 00:09:13
    that we classify as parasites
  • 00:09:15
    we have round worms uh like asterisk and
  • 00:09:18
    pinworm
  • 00:09:19
    uh we have flat worms that are not
  • 00:09:21
    segmented those are the schistosomes
  • 00:09:23
    and then finally we have the ones that
  • 00:09:25
    everybody is familiar with the tapeworms
  • 00:09:26
    that are segmented flat worms
  • 00:09:28
    and then there is a series of organisms
  • 00:09:30
    that are generally referred to as
  • 00:09:32
    ectoparasites
  • 00:09:34
    ecto meaning on so they don't live in
  • 00:09:36
    the host they live
  • 00:09:37
    on the host mosquitoes take our blood
  • 00:09:39
    for egg production
  • 00:09:41
    black flies suck our blood for egg
  • 00:09:42
    production we would consider fleas the
  • 00:09:44
    same thing
  • 00:09:45
    all of those are ectoparasites but
  • 00:09:47
    they're temporary parasites for the most
  • 00:09:49
    part
  • 00:09:50
    we know of a few that are not so
  • 00:09:51
    temporary though we can talk about head
  • 00:09:53
    lice we can talk about pubic lice and we
  • 00:09:55
    can talk about body lines
  • 00:09:56
    and in those cases they live on us
  • 00:09:59
    and they depend on us and we are their
  • 00:10:02
    home
  • 00:10:04
    in order for a parasitic infection to
  • 00:10:07
    take place
  • 00:10:08
    the parasites must first gain entry into
  • 00:10:11
    a suitable host
  • 00:10:13
    since parasites are perceived as being
  • 00:10:15
    everywhere
  • 00:10:16
    some of us think we can even catch them
  • 00:10:18
    by breathing in the air
  • 00:10:19
    this is not true there are really only
  • 00:10:22
    three different ways we can catch
  • 00:10:23
    the parasites the ones that we're
  • 00:10:24
    discussing and that is
  • 00:10:27
    we can eat them we can drink water
  • 00:10:30
    in which they have stages so that we can
  • 00:10:33
    catch them this way
  • 00:10:35
    there's even one we can catch by sexual
  • 00:10:36
    intercourse
  • 00:10:38
    but the vast majority of the ones that
  • 00:10:40
    we're really afraid of the ones that
  • 00:10:42
    cause the most suffering throughout the
  • 00:10:43
    world
  • 00:10:44
    are the ones that are transmitted by
  • 00:10:46
    arthropod vectors
  • 00:10:48
    a vector is generally thought of as
  • 00:10:51
    an organism that transmits a parasite
  • 00:10:55
    from one place to another from one stage
  • 00:10:57
    of its life cycle to another but we
  • 00:11:00
    don't
  • 00:11:00
    have to go to the parasites the
  • 00:11:01
    parasites will come to us they have
  • 00:11:03
    their own transportation system so to
  • 00:11:05
    speak
  • 00:11:08
    mosquito vectors are responsible for
  • 00:11:10
    transmitting some of the most
  • 00:11:11
    dangerous diseases on earth
  • 00:11:15
    one example is lymphatic filariasis
  • 00:11:20
    lymphatic filariasis which is also known
  • 00:11:22
    by its common name elephantiasis is a
  • 00:11:25
    vector-borne parasitic disease caused by
  • 00:11:28
    a
  • 00:11:29
    roundworm a nematode it's a very
  • 00:11:32
    widespread disease throughout the
  • 00:11:34
    tropics thought to
  • 00:11:36
    involve somewhere in the order of 120
  • 00:11:38
    million people or so
  • 00:11:39
    around the world for most people a
  • 00:11:42
    filariasis infection brings about only
  • 00:11:45
    mild side effects
  • 00:11:48
    but when the disease infests the
  • 00:11:50
    lymphatic system
  • 00:11:52
    severe pain and intense suffering result
  • 00:11:56
    the lymphatic channels can be in various
  • 00:11:58
    parts of the body
  • 00:12:01
    classically it's in the lower
  • 00:12:02
    extremities so the adult worms are in
  • 00:12:05
    the lymphatic channels of the legs
  • 00:12:08
    and it impedes the return flow of lymph
  • 00:12:10
    fluid
  • 00:12:12
    causing buildup of lymph fluid and
  • 00:12:16
    the subsequent swelling and then the
  • 00:12:19
    fibrotic reaction that the body has
  • 00:12:21
    over years and then the infections of
  • 00:12:24
    the skin that are caused
  • 00:12:26
    by the compromised lymphatic flow that
  • 00:12:29
    result in the fairly grotesque
  • 00:12:33
    classic elephantiasis of the lower
  • 00:12:35
    extremities
  • 00:12:36
    the common underlying result is
  • 00:12:40
    debility severe
  • 00:12:43
    inability to to perform one's one's
  • 00:12:46
    daily routine
  • 00:12:50
    the disease is very hard to diagnose in
  • 00:12:53
    its early stages
  • 00:12:54
    one of the the very frustrating things
  • 00:12:56
    about this
  • 00:12:58
    this parasitic infection is that in its
  • 00:13:01
    early stages it's it's clinically very
  • 00:13:04
    silent
  • 00:13:05
    so you can get fairly young children
  • 00:13:07
    that actually become infected with this
  • 00:13:09
    parasite
  • 00:13:10
    and unless you look in their blood to
  • 00:13:12
    see the
  • 00:13:13
    embryonic forms of the parasite you
  • 00:13:16
    wouldn't know that they were infected
  • 00:13:18
    and then very gradually over years as
  • 00:13:20
    they enter
  • 00:13:21
    puberty in adult life they will begin to
  • 00:13:25
    manifest
  • 00:13:26
    slight swellings of one leg or
  • 00:13:29
    a hydrocele or a swelling of the scrotum
  • 00:13:32
    that just gradually over time
  • 00:13:34
    gets bigger and bigger inexorably
  • 00:13:37
    once they reach that stage there's not
  • 00:13:41
    much that can be done medically to try
  • 00:13:44
    and cure them of that
  • 00:13:47
    parasites have lived both on and in us
  • 00:13:50
    since the beginning of man they have
  • 00:13:53
    evolved to develop specialized
  • 00:13:55
    techniques
  • 00:13:56
    to invade our bodies and evade our
  • 00:13:59
    defenses
  • 00:14:00
    while medical advances have bolstered
  • 00:14:02
    our ability to detect and treat
  • 00:14:04
    parasitic infections
  • 00:14:06
    the parasites continue their quest for
  • 00:14:09
    shelter
  • 00:14:09
    and sustenance within us
  • 00:14:14
    one method of infection is through our
  • 00:14:17
    dietary intake
  • 00:14:20
    imported foods have played a significant
  • 00:14:22
    part in the increase of parasitic
  • 00:14:24
    infections
  • 00:14:25
    in the u.s today
  • 00:14:28
    after the agricultural revolution and of
  • 00:14:30
    course with rapid transit
  • 00:14:32
    and with the ability to ship products
  • 00:14:35
    from one place to the other
  • 00:14:36
    in less than 18 hours parasites can come
  • 00:14:39
    to us now we don't have to go to them
  • 00:14:41
    any longer
  • 00:14:42
    so this raises the possibility for the
  • 00:14:44
    spread of parasites
  • 00:14:46
    in places that they never existed before
  • 00:14:49
    another interesting aspect of the whole
  • 00:14:51
    phenomenon of foodborne diseases is
  • 00:14:54
    a parasitic disease called anasakis
  • 00:14:58
    it's caused by a fish parasite
  • 00:15:01
    that is transmitted to humans when they
  • 00:15:03
    eat sushi which of course is uncooked
  • 00:15:06
    fish and this parasite which is a
  • 00:15:10
    normal parasite of fish can be acquired
  • 00:15:14
    by humans
  • 00:15:15
    and it causes a local invasion
  • 00:15:18
    of the gastrointestinal tract that in
  • 00:15:20
    some cases can mimic
  • 00:15:22
    stomach disease or appendicitis
  • 00:15:26
    in this country in the united states
  • 00:15:28
    we've had a
  • 00:15:29
    burgeoning sushi industry lots of people
  • 00:15:32
    eat sushi
  • 00:15:32
    in fact i eat sushi i eat it safely
  • 00:15:36
    why because we now know how this
  • 00:15:38
    parasite is transmitted uh
  • 00:15:40
    it requires the fish to sit around for a
  • 00:15:43
    while
  • 00:15:44
    in a non-fresh state now you can define
  • 00:15:46
    that any way you want
  • 00:15:47
    but in fact if you catch a fish and
  • 00:15:49
    place it on ice immediately
  • 00:15:51
    this parasite stays in the gut track to
  • 00:15:53
    those fish
  • 00:15:54
    if on the other hand you catch the fish
  • 00:15:56
    and it sits on the deck of the boat for
  • 00:15:57
    a while and warms up
  • 00:15:58
    the parasites will then crawl out of the
  • 00:16:00
    gut tissue into the meat of the fish
  • 00:16:02
    now when you put it on ice and bring it
  • 00:16:04
    in and make sushi out of that
  • 00:16:06
    you have the option at least of catching
  • 00:16:08
    that worm
  • 00:16:10
    we've become aware of that the fish that
  • 00:16:13
    are served in the sushi parlors of
  • 00:16:14
    america at least and i'm sure in japan
  • 00:16:16
    as well
  • 00:16:17
    is as fresh as the day it was caught
  • 00:16:20
    but not all food-borne parasitic
  • 00:16:22
    infections have been conquered
  • 00:16:25
    because of their insatiable appetite for
  • 00:16:27
    suitable hosts
  • 00:16:28
    parasites will always search out new
  • 00:16:31
    ways of infecting us
  • 00:16:33
    tapeworms are parasitic flatworms
  • 00:16:37
    that live in the intestine of humans
  • 00:16:40
    most commonly they're acquired through
  • 00:16:43
    the ingestion
  • 00:16:44
    of uncooked flesh that has the
  • 00:16:47
    larval stages of the parasite and there
  • 00:16:50
    appears to be
  • 00:16:51
    a tapeworm that corresponds to each type
  • 00:16:54
    of major
  • 00:16:55
    meat that's ingested for instance
  • 00:16:57
    there's a beef tapeworm
  • 00:16:58
    tina saginata there's a fish tapeworm
  • 00:17:02
    known as diphylobathrium latum there is
  • 00:17:05
    a pork tapeworm
  • 00:17:06
    named tinia soleum teeniacolium the pork
  • 00:17:10
    tapeworm has emerged as an
  • 00:17:11
    important infection not only in many
  • 00:17:14
    developing countries
  • 00:17:15
    but also in the united states as well
  • 00:17:18
    the parasite
  • 00:17:19
    is particularly prevalent in central
  • 00:17:22
    america
  • 00:17:22
    and in mexico and now the organism has
  • 00:17:26
    been
  • 00:17:27
    imported over the border to the point
  • 00:17:29
    where it has become a major infection
  • 00:17:32
    in u.s cities that are near these
  • 00:17:35
    countries so we find
  • 00:17:36
    high rates of tesolium infection in los
  • 00:17:40
    angeles and san diego and san antonio
  • 00:17:43
    and tucson arizona reason this is of
  • 00:17:46
    importance to note is because the larval
  • 00:17:49
    stages of the pork tapeworm
  • 00:17:52
    have been linked to an illness in the
  • 00:17:54
    brain
  • 00:17:56
    there is a syndrome associated with
  • 00:17:59
    solium
  • 00:18:00
    known as neurocystic psychosis that has
  • 00:18:03
    now become one of the leading causes of
  • 00:18:05
    epilepsy among children living in these
  • 00:18:08
    cities in the southwestern united states
  • 00:18:11
    the pork tapeworm the egg
  • 00:18:14
    when it's ingested into the human the
  • 00:18:16
    larva that emerges from that egg
  • 00:18:19
    and thinks it's in a pig the larva will
  • 00:18:22
    go and insist
  • 00:18:23
    in various parts of the human anatomy
  • 00:18:26
    unfortunately including and apparently
  • 00:18:28
    the parasite seems to have a tropism
  • 00:18:31
    for human neural tissue
  • 00:18:34
    so you can get cysts in the brain you
  • 00:18:37
    can get cysts in the eyes
  • 00:18:39
    you can get cysts in the musculature as
  • 00:18:41
    well
  • 00:18:42
    this disease is called cysticercosis
  • 00:18:47
    imported and undercooked food is not the
  • 00:18:49
    only way we can ingest a parasite
  • 00:18:53
    fresh clean water can never be taken for
  • 00:18:56
    granted
  • 00:18:57
    and the water we drink in our homes can
  • 00:19:00
    be tainted
  • 00:19:01
    one of the most common parasites in the
  • 00:19:03
    united states
  • 00:19:04
    besides cryptosporidium is giardia
  • 00:19:07
    lamblia
  • 00:19:08
    majority of lamblius is one of our more
  • 00:19:12
    photogenic parasites uh parasitologists
  • 00:19:14
    love to talk about giardia because
  • 00:19:16
    it looks like a little monkey face or it
  • 00:19:18
    has a personality it has a smile it has
  • 00:19:20
    a little flagella
  • 00:19:21
    people like to talk about it they don't
  • 00:19:23
    like to catch it so where do you catch
  • 00:19:25
    giardia
  • 00:19:26
    well you catch it from drinking
  • 00:19:27
    contaminated water by the breakdown
  • 00:19:30
    of public health practices which ensures
  • 00:19:32
    the safety of our drinking water
  • 00:19:34
    it's a constant struggle to maintain
  • 00:19:37
    filtered water supply for communities
  • 00:19:39
    that are
  • 00:19:40
    dependent upon those filtered water
  • 00:19:41
    supplies in reservoirs for instance
  • 00:19:44
    or natural bodies of water they have a
  • 00:19:46
    real problem ensuring the fact that the
  • 00:19:48
    giardia lamblia doesn't enter their
  • 00:19:49
    drinking water supply
  • 00:19:51
    and any time the filtration system fails
  • 00:19:54
    you can get outbreaks of giardia it's
  • 00:19:56
    well known that giardia cysts
  • 00:19:58
    can survive chlorination especially if
  • 00:20:02
    the chlorination
  • 00:20:03
    is not being done to adequate levels
  • 00:20:06
    so there have been large water-borne
  • 00:20:10
    outbreaks of giardiasis in the united
  • 00:20:12
    states
  • 00:20:14
    associated with either malfunctioning
  • 00:20:17
    or poorly designed municipal water
  • 00:20:19
    supplies
  • 00:20:20
    the diarrheal disease caused by giardia
  • 00:20:23
    is
  • 00:20:24
    somewhat different than the usual
  • 00:20:27
    diarrheal illness
  • 00:20:28
    because of where the parasite lives in
  • 00:20:30
    the human host
  • 00:20:32
    and the fact that in especially in heavy
  • 00:20:34
    infections
  • 00:20:35
    the parasite actually adheres to the
  • 00:20:38
    walls of the
  • 00:20:39
    small intestine but generally speaking
  • 00:20:41
    it can be treated with antibiotics
  • 00:20:45
    while gr diocese may cause us temporary
  • 00:20:47
    discomfort
  • 00:20:49
    waterborne disease in the tropics can
  • 00:20:51
    bring crushing illness
  • 00:20:54
    the guinea worm known formally as
  • 00:20:57
    dracunculus medinensis
  • 00:20:59
    is found throughout the tropical world
  • 00:21:01
    is transmitted through ingestion of
  • 00:21:03
    contaminant and water
  • 00:21:06
    there's a certain organism a crustacean
  • 00:21:09
    in that grows in fresh water that serves
  • 00:21:12
    as the intermediate host
  • 00:21:14
    for the disease and when humans ingest
  • 00:21:17
    water that has
  • 00:21:18
    an infected cyclops which is the name of
  • 00:21:21
    the intermediate host
  • 00:21:23
    they will acquire this disease it's a
  • 00:21:25
    worm that's about
  • 00:21:27
    twice the length of a yardstick in some
  • 00:21:29
    cases it lives in your subcutaneous
  • 00:21:31
    tissues and it seeks out the lowest part
  • 00:21:33
    of your body
  • 00:21:34
    and there the head of the worm elicits a
  • 00:21:36
    blister it's a visible blister you can
  • 00:21:38
    actually see the head of this worm under
  • 00:21:39
    the blister
  • 00:21:40
    when you step in the water the blister
  • 00:21:43
    bursts open
  • 00:21:44
    releasing larvae that the worm has
  • 00:21:45
    produced into the water column
  • 00:21:47
    and then you get to see this ugly
  • 00:21:49
    disfiguring blister on the end of your
  • 00:21:50
    foot
  • 00:21:51
    which you now have to do something about
  • 00:21:53
    and in most countries
  • 00:21:54
    what you do is you grab a small stick
  • 00:21:57
    and the head of the worm
  • 00:21:58
    wrap the head of the worm around this
  • 00:21:59
    stick and slowly every day
  • 00:22:02
    turn the stick slowly pulling the worm
  • 00:22:05
    out from your skin
  • 00:22:07
    if it should break you will experience
  • 00:22:10
    the worst anaphylactic reaction you can
  • 00:22:13
    possibly imagine
  • 00:22:14
    you'll get a sloughing of skin in the
  • 00:22:16
    region where the worm is
  • 00:22:18
    it will become secondarily infected with
  • 00:22:20
    bacteria and when it heals you'll have a
  • 00:22:22
    nasty scar for the rest of your life
  • 00:22:26
    another bloodthirsty parasite that
  • 00:22:28
    burrows through our skin
  • 00:22:30
    is the schistosome the schistosome
  • 00:22:33
    is endemic in parts of asia and africa
  • 00:22:36
    and utilizes a snail
  • 00:22:38
    as an intermediate host before infecting
  • 00:22:40
    humans
  • 00:22:42
    juvenile schistosomes called circaria
  • 00:22:45
    emerge from their snail host
  • 00:22:47
    into fresh water where they swim
  • 00:22:49
    frantically looking for the only host
  • 00:22:51
    where they can complete their
  • 00:22:52
    development
  • 00:22:53
    a human once the swimming circaria find
  • 00:22:57
    human skin
  • 00:22:58
    they eject their tail and utilize skin
  • 00:23:01
    dissolving enzymes to burrow through the
  • 00:23:03
    skin of the foot
  • 00:23:05
    and eventually into the bloodstream one
  • 00:23:08
    of its remarkable abilities
  • 00:23:11
    is its capacity to live in what should
  • 00:23:14
    be
  • 00:23:14
    the most inhospitable place on earth
  • 00:23:18
    an individual's bloodstream these worms
  • 00:23:20
    actually
  • 00:23:21
    live in blood vessels now think of it
  • 00:23:24
    if you were an infectious agent where is
  • 00:23:26
    the last place you would want to set up
  • 00:23:28
    shop
  • 00:23:29
    where you're being bombarded daily by
  • 00:23:31
    antibodies
  • 00:23:33
    being bombarded daily by white blood
  • 00:23:35
    cells
  • 00:23:36
    and yet here the schistosome not only
  • 00:23:39
    survives
  • 00:23:40
    but it thrives once the juveniles have
  • 00:23:44
    matured
  • 00:23:44
    the male and females pair up for life
  • 00:23:47
    where they mate
  • 00:23:48
    continuously producing and releasing
  • 00:23:50
    eggs
  • 00:23:51
    let's take the example of the bladder
  • 00:23:54
    schistosome
  • 00:23:55
    known as schistosoma hematobium with
  • 00:23:57
    this type of schistosomiasis
  • 00:23:59
    the egg has the ability to traverse
  • 00:24:02
    through the bladder wall
  • 00:24:05
    as the egg does this it elicits in a
  • 00:24:07
    host inflammatory response
  • 00:24:09
    that's also associated with bleeding as
  • 00:24:12
    a result people who harbor
  • 00:24:14
    bladder schistosomes develop blood in
  • 00:24:16
    their urine a condition known as
  • 00:24:18
    hematuria
  • 00:24:20
    a curious instance where
  • 00:24:23
    the presence of hematuria caused by
  • 00:24:26
    bladder schistosomes affected history
  • 00:24:28
    was when napoleon entered egypt
  • 00:24:32
    napoleon's troops it was prophesied
  • 00:24:35
    would be stricken by pharaoh's curse
  • 00:24:39
    should they choose to enter into egypt
  • 00:24:41
    and what was pharaoh's curse
  • 00:24:43
    it was male menstruation and sure enough
  • 00:24:46
    when many of his troops came into egypt
  • 00:24:48
    they acquired bladder schistosomiasis
  • 00:24:51
    and many of the troops believed that
  • 00:24:53
    this was the prophecy
  • 00:24:55
    of pharaoh's curse fulfilled another
  • 00:24:58
    fascinating parasitic disease
  • 00:25:00
    is one called oncocerciasis
  • 00:25:03
    the common name of which is river
  • 00:25:04
    blindness this is a
  • 00:25:06
    parasitic disease caused by a roundworm
  • 00:25:09
    parasite
  • 00:25:10
    of man that in its clinical
  • 00:25:14
    end stages causes a very devastating and
  • 00:25:16
    irreversible
  • 00:25:18
    blinding disease it's a parasite
  • 00:25:21
    that is transmitted from human to human
  • 00:25:24
    by the bite of a black fly
  • 00:25:26
    which is the vector the black fly breeds
  • 00:25:30
    in fast flowing streams
  • 00:25:33
    and therefore the disease is most
  • 00:25:36
    endemic
  • 00:25:37
    in the valleys of these streams and
  • 00:25:40
    thus the name river blindness after the
  • 00:25:43
    vector
  • 00:25:44
    bites the human it deposits the
  • 00:25:47
    larval worms which invade the skin
  • 00:25:51
    and eventually end up forming a nodule
  • 00:25:55
    under the skin where the adult worms
  • 00:25:58
    develop
  • 00:25:59
    while they're in this fibrous nodule
  • 00:26:02
    under the skin
  • 00:26:04
    the adult worms shed on the order of
  • 00:26:06
    three to five
  • 00:26:07
    thousand microfilarii or larval worms
  • 00:26:10
    per day
  • 00:26:12
    per adult these larval worms
  • 00:26:15
    instead of entering the bloodstream
  • 00:26:18
    remain
  • 00:26:18
    in the subcutaneous tissue and migrate
  • 00:26:22
    through the subcutaneous tissue
  • 00:26:24
    causing changes to the skin that can
  • 00:26:27
    manifest in such ways as
  • 00:26:29
    very hypoelastic skin
  • 00:26:33
    baggy skin as the disease progresses
  • 00:26:36
    and the number of larval worms in the
  • 00:26:38
    subcutaneous tissue increase
  • 00:26:40
    they eventually gain access to the
  • 00:26:42
    tissues of the eye
  • 00:26:44
    and cause microcalcifications which
  • 00:26:48
    over time build up and cause the
  • 00:26:50
    blindness
  • 00:26:54
    [Music]
  • 00:27:00
    this is where they slit my truth and had
  • 00:27:03
    some sort of plastic tube
  • 00:27:08
    the iv site went bad here and they cut
  • 00:27:11
    it out
  • 00:27:12
    and left me with this car and i also
  • 00:27:15
    have the scarf for my feeding tube
  • 00:27:17
    my body is scarred now
  • 00:27:21
    thirty-four-year-old haslam bostwick is
  • 00:27:23
    a native of south america
  • 00:27:24
    who lives in fort lauderdale florida
  • 00:27:28
    hasland knows a lot about one particular
  • 00:27:30
    parasite
  • 00:27:31
    plasmodium falciparum
  • 00:27:34
    it is the most deadly of all parasites
  • 00:27:37
    and more commonly known
  • 00:27:39
    as malaria
  • 00:27:40
    [Music]
  • 00:27:42
    i go into the interior of ghana very
  • 00:27:44
    often i used to
  • 00:27:46
    spend up to 10 days in there at the time
  • 00:27:50
    and in order to make sure that i don't
  • 00:27:53
    come in to cut it doesn't anything
  • 00:27:55
    nothing
  • 00:27:55
    bites me was i would make sure that my
  • 00:27:58
    tent was sprayed before i go to bed at
  • 00:28:00
    night
  • 00:28:01
    while i'm outdoor i make sure that my
  • 00:28:03
    body is totally covered so nothing could
  • 00:28:05
    bite me
  • 00:28:08
    in the spring of 1999 haslam had her
  • 00:28:11
    blood checked for malaria
  • 00:28:13
    when she returned from a trip to oversee
  • 00:28:15
    a gold mine she owns in guyana
  • 00:28:18
    she wasn't feeling well but her tests
  • 00:28:20
    proved negative
  • 00:28:22
    so hasland took her son on a school trip
  • 00:28:24
    to washington dc
  • 00:28:27
    she became weaker more nauseous three
  • 00:28:29
    days into the trip
  • 00:28:31
    haslam took to her bed
  • 00:28:36
    so i lied down and then i got up later
  • 00:28:38
    on went to the bathroom and
  • 00:28:39
    went back to bed and when i went back to
  • 00:28:42
    bed i never got back up again
  • 00:28:44
    haslam bostwick slipped into a coma she
  • 00:28:48
    was taken over by the malaria parasites
  • 00:28:51
    hasland joined the ranks of 250 million
  • 00:28:54
    victims around the globe
  • 00:28:56
    who contract malaria each year
  • 00:28:59
    three million of those people die and
  • 00:29:02
    it's the young who suffer the most
  • 00:29:05
    every 30 seconds of every hour of every
  • 00:29:08
    day
  • 00:29:09
    the malaria parasite kills a child
  • 00:29:13
    the research done over even the last 50
  • 00:29:15
    years
  • 00:29:16
    have not been able to reduce the
  • 00:29:18
    mortality
  • 00:29:20
    the in-hospital fatality rate
  • 00:29:23
    of severe malaria in children in the
  • 00:29:25
    tropics in primary care hospitals in the
  • 00:29:28
    tropics
  • 00:29:29
    one percent nothing that we've done
  • 00:29:33
    has been able to reduce the mortality of
  • 00:29:35
    severe malaria
  • 00:29:37
    malaria had been a mystery for centuries
  • 00:29:40
    no one knew exactly where it came from
  • 00:29:43
    nor how it was passed from victim to
  • 00:29:45
    victim
  • 00:29:46
    the evil illness seemed simply to emerge
  • 00:29:49
    from the stale air around swamps
  • 00:29:52
    in fact the literal translation of
  • 00:29:54
    malaria is
  • 00:29:55
    bad air in 1880
  • 00:29:59
    a protozoan parasite was found living in
  • 00:30:02
    the blood of malaria patients
  • 00:30:06
    the female anopheles mosquito was soon
  • 00:30:09
    identified as the vector
  • 00:30:11
    for the malaria parasite
  • 00:30:19
    sixty years later malaria was still the
  • 00:30:22
    leading cause of sickness and death in
  • 00:30:24
    humans on earth
  • 00:30:27
    the medicine quinine made from the bark
  • 00:30:29
    of the cincona tree
  • 00:30:31
    had been used to ease symptoms for 400
  • 00:30:33
    years
  • 00:30:34
    but it took until the 1950s to find hope
  • 00:30:37
    in a weapon that would wipe out
  • 00:30:39
    malaria's carrier
  • 00:30:42
    chlorinated hydrocarbon insecticide ddt
  • 00:30:47
    there was nothing quite like it before
  • 00:30:49
    and there has been nothing like it since
  • 00:30:51
    here was a chemical that could be
  • 00:30:53
    sprayed on the walls of a house
  • 00:30:55
    and for up to six months any insect that
  • 00:30:57
    rested on that surface
  • 00:30:58
    would die it was then thought to be
  • 00:31:01
    non-toxic to humans
  • 00:31:03
    and it was inexpensive to manufacture
  • 00:31:06
    the female anopheles mosquito was public
  • 00:31:08
    enemy number one
  • 00:31:10
    and world health officials had a brand
  • 00:31:12
    new weapon
  • 00:31:14
    eradication efforts were effective in
  • 00:31:16
    north america and europe
  • 00:31:18
    but after a decade of trying to
  • 00:31:19
    annihilate the mosquito in africa
  • 00:31:21
    india and asia the success of ddt slowed
  • 00:31:26
    war corruption inaction famine
  • 00:31:29
    and a host of other problems detracted
  • 00:31:31
    from the battle
  • 00:31:32
    against malaria by the late 1970s
  • 00:31:36
    the world health organization bitterly
  • 00:31:38
    admitted that malaria was back
  • 00:31:40
    and worse than ever today only the hiv
  • 00:31:45
    virus comes close to the destruction
  • 00:31:47
    malaria brings upon this earth
  • 00:31:52
    it's estimated by some economists that
  • 00:31:55
    malaria alone reduces the gross domestic
  • 00:31:57
    product of the countries in sub-saharan
  • 00:31:59
    africa by about one percent
  • 00:32:03
    perhaps even more that translates into
  • 00:32:06
    billions of dollars of loss
  • 00:32:09
    in those countries every year
  • 00:32:13
    so it has an enormous impact in every
  • 00:32:16
    military campaign
  • 00:32:17
    in which u.s forces have been involved
  • 00:32:19
    in the last hundred years
  • 00:32:21
    where malaria was transmitted we've
  • 00:32:24
    always had more casualties to malaria
  • 00:32:26
    than we've had from hostile fire
  • 00:32:28
    that means from a military perspective
  • 00:32:31
    that malaria has tremendous
  • 00:32:33
    mission aborting potential
  • 00:32:36
    the swamps around haslam bostwick's
  • 00:32:39
    south american gold mine
  • 00:32:40
    were a perfect breeding ground for the
  • 00:32:42
    anopheles mosquito
  • 00:32:45
    as the mosquito fed on hasland's blood
  • 00:32:47
    in its nightly ritual
  • 00:32:49
    it released thousands of thread-like
  • 00:32:51
    malaria parasites
  • 00:32:52
    that were stored in its salivary glands
  • 00:32:56
    for 12 days haslan would go without
  • 00:32:59
    symptoms while parasites invaded her
  • 00:33:01
    liver
  • 00:33:02
    and transformed into organisms that
  • 00:33:04
    moved on to her red blood cells
  • 00:33:06
    the tiny creatures divided and
  • 00:33:08
    multiplied by the millions
  • 00:33:10
    they became so numerous that her red
  • 00:33:12
    blood cells exploded
  • 00:33:14
    by the time haslin fell into a coma
  • 00:33:17
    parasites were shutting down
  • 00:33:18
    most of her vital organs including her
  • 00:33:21
    brain
  • 00:33:22
    the only organ that was functioning was
  • 00:33:24
    my heart
  • 00:33:25
    everything else had already shut down by
  • 00:33:28
    the time i got to the hospital
  • 00:33:30
    and they had to
  • 00:33:33
    pretty much they had to put catheters
  • 00:33:36
    and whatever else they had to put in me
  • 00:33:40
    dr stephen hoffman was rushed in to work
  • 00:33:43
    with haslan
  • 00:33:44
    so what was going on was these parasites
  • 00:33:47
    were binding to these small blood
  • 00:33:48
    vessels
  • 00:33:49
    in her brain and blocking up blood flow
  • 00:33:54
    if there's no blood flow then no oxygen
  • 00:33:56
    gets to your brain
  • 00:33:57
    and you slip into a coma after centuries
  • 00:34:01
    of suffering
  • 00:34:02
    and death decades after the discovery
  • 00:34:04
    that malaria is a parasite
  • 00:34:06
    and research into a cure there is still
  • 00:34:09
    no effective modern drug to combat
  • 00:34:12
    malaria in its late stages
  • 00:34:14
    and there is no practical vaccine
  • 00:34:16
    against malaria
  • 00:34:18
    we are in a situation where the two
  • 00:34:20
    major drugs
  • 00:34:21
    in this world used for treating severe
  • 00:34:24
    malaria cerebral malaria severe malarial
  • 00:34:26
    anemia
  • 00:34:28
    hyper paracetamia high levels of
  • 00:34:30
    parasites in the bloodstream
  • 00:34:32
    are quinine and artemisinin derivatives
  • 00:34:36
    both of those have been available for
  • 00:34:38
    hundreds if not thousands of years
  • 00:34:41
    it's not that we haven't developed new
  • 00:34:43
    drugs for treating the parasite
  • 00:34:45
    but that the parasite has either
  • 00:34:47
    developed resistance to those drugs or
  • 00:34:49
    they're actually not as good
  • 00:34:51
    as these age-old remedies
  • 00:34:55
    through the developed world's best
  • 00:34:57
    medical efforts hasland did stabilize
  • 00:35:00
    and miraculously she survived after five
  • 00:35:03
    weeks of devastating illness
  • 00:35:05
    haslam responded to treatment and has
  • 00:35:08
    been malaria free
  • 00:35:09
    ever since
  • 00:35:13
    this this particular parasite kills
  • 00:35:16
    and not too many people can survive to
  • 00:35:19
    tell a story
  • 00:35:21
    because especially getting to the point
  • 00:35:23
    where i was
  • 00:35:25
    because i should have been dead
  • 00:35:29
    i should not be here sitting with
  • 00:35:31
    talking to you today i should really be
  • 00:35:32
    dead
  • 00:35:35
    efforts to eradicate and treat the
  • 00:35:37
    terrifying destruction of parasites
  • 00:35:40
    all over the world meet with varied and
  • 00:35:42
    intermittent success
  • 00:35:45
    in the case of vector-borne parasites
  • 00:35:48
    african governments have attempted to
  • 00:35:49
    eliminate the vectors
  • 00:35:51
    the flies and mosquitoes and other
  • 00:35:53
    insects that carry parasites for river
  • 00:35:55
    blindness
  • 00:35:56
    elephantiasis and malaria
  • 00:36:02
    these efforts have slowed the spread of
  • 00:36:04
    some infections
  • 00:36:05
    but many scientists argue that
  • 00:36:07
    eradication of parasites
  • 00:36:09
    may not be possible we've actually never
  • 00:36:11
    been able to control
  • 00:36:13
    to the point of extinction any parasitic
  • 00:36:15
    infection
  • 00:36:16
    the only disease producing agent we've
  • 00:36:20
    ever been able to get rid of is smallpox
  • 00:36:22
    and that's because smallpox only
  • 00:36:24
    infected the human and no other
  • 00:36:26
    host some of these parasites can infect
  • 00:36:28
    multiple
  • 00:36:29
    hosts you can have reservoirs out there
  • 00:36:31
    so even if you could affect cures in
  • 00:36:33
    people
  • 00:36:34
    you still couldn't get rid of it in the
  • 00:36:35
    animal populations it might also harbor
  • 00:36:37
    the same stages
  • 00:36:39
    so even if you could control everything
  • 00:36:40
    in the human population you could still
  • 00:36:42
    reintroduce it every now and then
  • 00:36:44
    because of these animal reservoirs
  • 00:36:48
    if eradication isn't an option then
  • 00:36:50
    controlling the spread of infection is
  • 00:36:52
    the answer to limiting parasitic
  • 00:36:54
    outbreaks
  • 00:36:56
    one control success story is the
  • 00:36:58
    onco-circiasis control program
  • 00:37:02
    when oncochiasis was at its height
  • 00:37:06
    in the late 60s and early 70s
  • 00:37:10
    it became evident that this disease was
  • 00:37:12
    a major
  • 00:37:13
    impediment to successful development
  • 00:37:16
    particularly of these countries in west
  • 00:37:18
    africa where it was so highly endemic
  • 00:37:21
    because of that
  • 00:37:22
    the world bank the who
  • 00:37:26
    and other international organizations
  • 00:37:28
    banded together
  • 00:37:29
    to form the encore crisis control
  • 00:37:31
    program
  • 00:37:32
    which has in its 25 years of existence
  • 00:37:35
    had a
  • 00:37:36
    major impact on blocking the
  • 00:37:39
    transmission of the disease
  • 00:37:41
    protecting the vision of over 600 000
  • 00:37:44
    africans
  • 00:37:45
    in west africa and allowing somewhere in
  • 00:37:49
    the order of 15 million
  • 00:37:50
    children in this area to be able to grow
  • 00:37:53
    up
  • 00:37:54
    without the threat of blinding onco
  • 00:37:56
    psychiatrists
  • 00:37:59
    the guinea worms story is one of our
  • 00:38:02
    shining lights in terms of parasite
  • 00:38:04
    controls
  • 00:38:06
    it's found throughout the tropics
  • 00:38:07
    throughout africa throughout the middle
  • 00:38:09
    east throughout
  • 00:38:10
    india and even in south america as well
  • 00:38:13
    it's intermediate host that is it lives
  • 00:38:15
    in other things besides humans it lives
  • 00:38:17
    in this little water
  • 00:38:18
    flea and by filtering out the water flea
  • 00:38:21
    you can get rid of the guinea one and we
  • 00:38:23
    taught people how to do that
  • 00:38:25
    they went and did it and we've
  • 00:38:27
    controlled this infection now in all but
  • 00:38:28
    13 countries throughout the world
  • 00:38:30
    used to be in hundreds of countries
  • 00:38:34
    in the developed world new water
  • 00:38:36
    treatment practices have been developed
  • 00:38:38
    to keep
  • 00:38:38
    out cryptosporidium parasites
  • 00:38:41
    milwaukee spent 80 million dollars
  • 00:38:43
    building a new water plant
  • 00:38:46
    but the tragedy in milwaukee brought
  • 00:38:47
    attention to the daily efforts being
  • 00:38:49
    made
  • 00:38:50
    on the part of water treatment officials
  • 00:38:52
    to ensure that our drinking water
  • 00:38:54
    remains safe the lessons that we learned
  • 00:38:57
    in milwaukee is
  • 00:38:59
    you need to be prepared you need to know
  • 00:39:01
    the capabilities and the vulnerabilities
  • 00:39:03
    of your water treatment system
  • 00:39:05
    one can never say this will happen again
  • 00:39:07
    but one can never say it won't
  • 00:39:09
    and so until there's assurance
  • 00:39:12
    between the health department the water
  • 00:39:14
    officials and others that you're as
  • 00:39:16
    prepared as you can be
  • 00:39:18
    you're at risk david leiby of the
  • 00:39:22
    american red cross
  • 00:39:23
    believes the milwaukee outbreak was a
  • 00:39:25
    wake-up call
  • 00:39:26
    the sheer size of the incident suggests
  • 00:39:29
    that
  • 00:39:31
    there's a potential for this type of
  • 00:39:32
    thing to occur in the future
  • 00:39:34
    i mean even though our water supply like
  • 00:39:35
    our blood supply is very safe as well
  • 00:39:37
    and great measures are taken to
  • 00:39:39
    prevent these kind of instances or these
  • 00:39:42
    kind of occurrences from happening
  • 00:39:44
    however it just points out the fact that
  • 00:39:46
    parasites can in fact be very
  • 00:39:48
    opportunistic
  • 00:39:50
    and then if there is a possibility of
  • 00:39:53
    them getting into a system in this case
  • 00:39:55
    a water system
  • 00:39:56
    which they are allowed an opportunity to
  • 00:39:59
    grow and develop
  • 00:40:00
    and to replicate then they certainly can
  • 00:40:02
    take advantage of it
  • 00:40:05
    some see a future in biological controls
  • 00:40:08
    putting parasites at war with each other
  • 00:40:12
    introduce a benign echinostome flute to
  • 00:40:15
    the host of a parasite like the
  • 00:40:17
    schistosome fluke
  • 00:40:18
    in hopes that the benign flute will
  • 00:40:21
    attack and kill
  • 00:40:22
    its harmful cousin
  • 00:40:25
    the snail is infected with this evil
  • 00:40:28
    schistosome
  • 00:40:29
    and along comes this nice a kind of
  • 00:40:32
    stone that has a mouth
  • 00:40:34
    and a gut and it seeks out the
  • 00:40:37
    schistosome in the snail
  • 00:40:39
    and wammo it it sucks it up it swallows
  • 00:40:42
    it
  • 00:40:43
    and the schistosome uh larval stage is
  • 00:40:46
    gone
  • 00:40:46
    uh and this is a marvelous biological
  • 00:40:50
    adaptation
  • 00:40:51
    whereby this tug of war is going on in
  • 00:40:54
    the snail and the
  • 00:40:56
    schistosome this evil schistosome is
  • 00:40:59
    destroyed by this nice
  • 00:41:00
    kind of stone the idea of biological
  • 00:41:04
    control in some respects
  • 00:41:05
    is very attractive as opposed to
  • 00:41:08
    something like ddt which is very harmful
  • 00:41:11
    to the environment if you could have a
  • 00:41:13
    biological control
  • 00:41:15
    for instance another animal eating the
  • 00:41:17
    intermediate host or one of the the
  • 00:41:19
    vectors of a parasite
  • 00:41:21
    you know that's a great idea because
  • 00:41:23
    that doesn't involve something that
  • 00:41:24
    generally harms the environment or
  • 00:41:26
    disrupts the ecology at least in most
  • 00:41:28
    cases
  • 00:41:30
    another avenue of protection is the
  • 00:41:32
    development of a vaccine against
  • 00:41:34
    parasitic infections
  • 00:41:38
    dr stephen hoffman and his team at the
  • 00:41:40
    navy medical research center in bethesda
  • 00:41:42
    maryland
  • 00:41:43
    are developing groundbreaking vaccines
  • 00:41:45
    for malaria
  • 00:41:47
    the team begins with thousands of
  • 00:41:49
    anopheles mosquitoes
  • 00:41:51
    from the research centers in sectary
  • 00:41:54
    volunteers are bitten by
  • 00:41:55
    malaria-infected mosquitoes
  • 00:41:57
    that have been exposed to radiation the
  • 00:42:00
    radiation weakens the malaria parasites
  • 00:42:03
    harbored within the infected mosquitoes
  • 00:42:06
    the weakened parasites evoke responses
  • 00:42:08
    from the volunteers autoimmune system
  • 00:42:12
    after thousands of these responses the
  • 00:42:14
    volunteers develop immunity to malaria
  • 00:42:19
    while progress towards a workable
  • 00:42:21
    vaccine is made every day
  • 00:42:24
    the complex nature of parasites creates
  • 00:42:27
    a moving target for medical science
  • 00:42:30
    they have multiple antigens or proteins
  • 00:42:34
    that are expressed
  • 00:42:35
    on their surface at different courses in
  • 00:42:37
    their life cycle
  • 00:42:39
    that makes the design of a vaccine
  • 00:42:41
    almost impossible
  • 00:42:46
    the more we learn about these parasites
  • 00:42:48
    the more respect we gain for
  • 00:42:50
    their side of the life cycle and the
  • 00:42:52
    more respect we gain
  • 00:42:54
    for the immense amount of selection
  • 00:42:57
    those parasites have caused our biology
  • 00:42:59
    to undergo
  • 00:43:04
    the ability of these organisms to infect
  • 00:43:06
    new hosts and infect virtually every
  • 00:43:08
    animal that we know
  • 00:43:09
    there's just so many different varieties
  • 00:43:12
    of parasites and so many complex things
  • 00:43:14
    that you
  • 00:43:15
    you can learn as well simple things
  • 00:43:20
    there's nothing easy about studying
  • 00:43:22
    parasitic organisms
  • 00:43:24
    they tend to be very difficult to
  • 00:43:26
    maintain in the laboratory
  • 00:43:28
    it tends to be very difficult to get
  • 00:43:29
    large numbers of organisms to study
  • 00:43:32
    as a result doing biochemistry on these
  • 00:43:35
    organisms is difficult doing genetics on
  • 00:43:37
    these organisms are difficult
  • 00:43:45
    parasitologists scientists who study
  • 00:43:47
    parasites
  • 00:43:48
    tend to be of a very special breed
  • 00:43:51
    there's something else that motivates
  • 00:43:53
    parasitologists to study these organisms
  • 00:43:56
    that would not ordinarily motivate
  • 00:43:58
    a person studying another class of
  • 00:44:00
    organisms the wonder of it all and the
  • 00:44:02
    the complexity of what we see in these
  • 00:44:05
    organisms
  • 00:44:06
    going from single cell organisms to very
  • 00:44:08
    complex organisms from
  • 00:44:11
    parasites that you have to look at under
  • 00:44:13
    a microscope to
  • 00:44:14
    tapeworms found in whales that are 100
  • 00:44:16
    feet long
  • 00:44:19
    the ultimate goal of studying parasites
  • 00:44:22
    and to learn about their biologies
  • 00:44:24
    is to ultimately exercise some control
  • 00:44:28
    over the way they spread
  • 00:44:32
    my cousin rabbi felizowski told me about
  • 00:44:36
    a hebrew concept
  • 00:44:37
    which he calls tikkun olam and it means
  • 00:44:41
    to better the world it kind of refers to
  • 00:44:44
    the fact that
  • 00:44:47
    an individual's obligation in life is
  • 00:44:50
    to try to want to better the world and i
  • 00:44:52
    think that's the one unifying feature
  • 00:44:54
    i've always seen
  • 00:44:55
    among my colleagues in parasitology is
  • 00:44:58
    no matter what particular parasite
  • 00:45:00
    they're studying
  • 00:45:01
    there is some humanitarian motivation in
  • 00:45:04
    wanting to study these classic organisms
  • 00:45:21
    [Music]
  • 00:45:38
    you
الوسوم
  • parasites
  • malaria
  • cryptosporidium
  • public health
  • waterborne diseases
  • tropical diseases
  • Lyme disease
  • vaccine development
  • infection control
  • schistosomiasis