today's video is sponsored by squarespace the only platform worth considering when you're ready to
start your next great website this is the age of creation people don't just consume stuff on the
web anymore they make it either you've got a great idea for a website or you probably know someone
who does and when it's time to move that project from your head to the screen in front of you
that's where our friends at squarespace come in it's the perfect web tool to help
you fashion the internet into whatever you want it to be maybe they're hands-on type
with lots of opinions and ideas about what exactly your website should look like if so
fantastico squarespace gives you all the customization options you could ever want
but if you're a no talent non-designing person like me well squarespace has beautiful templates
that just work you just go in you choose a template minimal thought change a few things
around and boom it looks like a beautiful custom website but it took you less than an afternoon
speaking from personal experience and once you're done setting up your website locking
in the name maybe playing with some of the colors there are tons of extra features email campaigns
patronage portals social integrations member-only areas analytics commercials 24 7 customer support
everything you need is in one place so when you're ready to get started go to squarespace.com for a
free trial and when you're ready to launch go to squarespace.com forward slash brain food
and you'll get 10 off your first purchase of a website or a domain and now today's video
in his aphorisms written around 380 bc ancient greek physician hippocrates describes a truly
horrifying case of disease the master of a large ship mashed the index finger of his right hand
with the anchor seven days later a somewhat foul discharge appeared then trouble with his tongue he
complained he could not speak properly his drawers became pressed together his teeth were locked
then symptoms appeared on his neck on the third day opus thottenos appeared with sweating six days
after the diagnosis was made he died the ship's master was suffering from tetanus better known as
lock draw a disease that still affects 209 000 people and kills 59 000 worldwide every year if
you've ever heard of tetanus it's probably through being vaccinated against it before
attending school or perhaps you have heard that you can contract the disease from stepping on
or scratching yourself with a rusty nail but is this really true can such a seemingly minor injury
really lead to dramatic symptoms well yeah but not for the reasons that you might think tetanus
has been humanity's constant companion since the dawn of known history the first description of
the disease appears in the ebers papyrus ancient egyptian medical treatise written around 1500 bce
though this is thought to have been then copied from an earlier source dating back as far as
3000 bce the disease gets its name from the ancient greek word tetanus meaning taught or
to stretch reference to the stiffness and violent muscle spasms characteristic of the affliction in
severe cases these spasms can be so violent as to cause the sufferer to fully arch their back
and neck this is what hypocrisy refers to in his original description as officer loss they can even
tear muscles or break bones while for thousands of years the cause of tetanus remained a mystery
as with most diseases there was no shortage of attempts to develop a cure the ancient chinese
for example used acupuncture above the patient's ears while the ancient greeks and romans working
from the for humours model of medicine attempted to induce sweating by placing patients near fires
wrapping them in oil-soaked cloths or making them drink copious amounts of wine and for more on the
for humour's theory and its massive impact on the history of medicine please check out our previous
video what's up with the increasingly popular practice of modern medical leeches later medieval
and renaissance doctors recommended even more unpleasant treatments such as covering the patient
in manure which as we shall see likely made the situation even more beyond the obvious ways still
even in ancient times it was well understood that tetanus had something to do with open wounds that
the symptoms typically appeared within a week or so of the inciting injury with greek physician
erytheus of kappa dosha writing in the first century ce the causes of these complaints are many
for some are apt to supervene on the wound of a membrane or of muscles and women also suffer from
this spasm after abortion and in this case they seldom recover while hippocrates concludes his
description of the disease with such persons are seized with tetanus either die within four days or
if they pass these they recover with the advent of modern weaponry such as explosive artillery shells
capable of inflicting large numbers of deep soil contaminated wounds tetanus became a leading cause
of death for soldiers on the battlefield during the american civil war for example one in 500 men
died of tetanus from infected wounds the disease was also a common and feared post-operative
complication even after the adoption of antiseptic surgical techniques and even became associated
with all things american 4th of july celebrations indeed in the years before the widespread
availability of vaccines the holiday was commonly known as the bloody fourth due to the high number
of tetanus deaths resulting from accidents involving fireworks and firecrackers however
it was not until the late 19th century in the development of the germ theory of disease that the
true cause of tetanus was at last discovered the first breakthrough came in 1884 when anthony carle
and giorgio retone pathologists at the university of turin injected past from human tetanus victims
into rabbits the animals proceeded to contract deadness demonstrating that the disease was
transmissible and likely caused by a microorganism that same year german researcher arthur nicolai
discovered that certain bacteria commonly found in the soil produced powerful neurotoxins which
when injected into lab animals produced the same symptoms as tetanus this link was confirmed by
japanese researcher kitasato shibasaburo who in 1891 isolated the causative pathogen from a
human tetanus victim the anaerobic soil bacterium clostridium tatani shibasabiro's breakthrough
however went far beyond discovering the cause of tetanus while working at the university of
berlin shibasaburo and his german researcher emil von bering discovered that when rats and other
lab animals were injected with tetanus toxin their bodies produced a substance capable of
neutralizing said toxin as well as the tetanus bacterium when the substance which she basabiro
and von bering called antitoxin was extracted from one animal's blood serum and injected into another
it both cured existing tetanus infections and provided protection against future infections
this technique known as serum therapy or antitoxin therapy was among the most important breakthroughs
in the history of medicine indeed such was the impact of tetanus antitoxin that during the first
world war the anton powers suffered only one case of tetanus per 5 000 wounded soldiers antitoxins
were later developed for more dangerous and infectious diseases such as diphtheria and scarlet
fever saving millions of lives and winning a milvon bearing the 1901 nobel prize in physiology
and medicine in the early years antitoxin was produced commercially by injecting horses with
bacteria extracting their blood and purifying the serum while effective at producing large
quantities of serum this technique did suffer from a number of drawbacks one there was serum sickness
a cluster of symptoms such as rashes joint pain fever and swollen lymph glands that arose five to
ten days after being injected with the antitoxin this effect was first noted in 1906 by austrian
pediatrician clemens von piquette and hungarian american pediatrician bella schtick who determined
that it was caused by the victim's immune system reacting to foreign horse proteins in the serum
to describe this effect von paquette and schtick combined the greek words alos meaning other and
ergon meaning work to coin a now familiar word allergy the discovery of serum sickness and other
allergic reactions allowed bellastic to develop a simple and effective test to determine if someone
was immune to diphtheria which became known as the ship test in this procedure a small dose of
diphtheria toxin was injected into one arm and heat inactivated toxin into the other arm as a
control if the skin around the first injection became red and swollen then the person did not
have sufficient antitoxins better known today as antibodies to fight off a diphtheria infection if
little or no swelling occurred then the person was immune a french physician charlemanto later
adapted the schick test to the bacteria protein tuberculin creating the eponymous manto test still
the standard diagnostic test for tuberculosis infection in many parts of the world another major
downside of horse-produced anti-toxin was the risk of contamination on the 2nd of october 1901
american horse named jim who had produced nearly 30 liters of diphtheria serum over his lifetime
was found to have contracted tetanus and had to be euthanized seventeen days later four young
children in saint louis missouri veronica keenan and bessie viola and frankie baker were given
diphtheria antitoxin manufactured from jim's serum within four days veronica berry and viola were
dead of tetanus this incident and others spurred research into safer alternatives to traditional
antitoxin in 1924 french biologist gaston ramon came up with a solution toxoid or anatoxin a
version of the tetanus or diphtheria toxin treated with heat and formaldehyde such that it was no
longer toxic to humans but still retained its immunologic properties a perfected version of
tetanus toxoid was used to protect u.s troops during world war ii and in 1948 was combined
with the vaccines for diphtheria and pertussis aka whooping cough to create the dpt vaccine
still given to school children around the world even today yet traditional tetanus antitoxin
never really went away and survives to this day in the form of tetanus immunoglobulin or tig
unlike the first antitoxins however tig is manufactured not from the blood of horses but
volunteer human donors who are injected with a small dose of bacterial toxin prior to donating
blood now moving away from that diversion into the fascinating world of immunology let's get back to
tetanus about which much has been learned since the late 19th century as previously mentioned
tetanus is caused by clostridium tatarnai a rod-shaped bacterium around 2.5 microns
in length an anaerobic bacterium that thrives in oxygen-free environments cetatani commonly found
in the soil as well as in the intestinal tracts and feces of many animals including cats dogs
cattle sheep chickens horses mice and rats while the bacterium itself is heat sensitive and cannot
survive in the presence of oxygen for long outside the body of an animal seed tani transforms itself
into a dormant spore which is a different beast altogether tetanus spores are extremely resilient
impervious to most antiseptics and capable of surviving typical sterilization temperatures
of 120 celsius for up to 10 to 15 minutes this makes tetanus extremely difficult to
eradicate even in an otherwise sterile hospital environment ceterani typically enters the body
via a puncture wound and once in the anaerobic environment beneath the skin it begins to multiply
as it does so it produces two toxins as waste products tetanular sin and tetanospasmin which
slowly spread throughout the victim's nervous system tetanus spasmin more generally known as the
tetanus toxin is one of the most potent poisons known to science with an ld50 that is the dose
which kills 50 of a test sample of lab animals of 2.5 nanograms per kilogram of body weight
it is second only to botulinum toxin produced by sea tetany's cousin clostridium botulinum
the bacterium that causes botulism food poisoning tetanus spasm inhibits the function of inhibitory
neurons which prevents motor neurons from firing and allows muscles to relax after contraction
this inhibition causes the uncontrolled muscle spasms or tetany characteristics of tetanus
the incubation period of tetanus that is the time between initial infection and the onset
of symptoms can be up to several weeks or even months but is usually around 10 days typically
the farther away the injury site from the central nervous system the longer the incubation period
initial symptoms include stiffness and pain and the muscles of the shoulders back neck and jaw
speaking and swallowing become increasingly difficult until the jaw muscles tighten so much
that it becomes difficult or impossible to open the mouth the symptom known as christmas which
gives tetanus its more common name of lockjaw this is followed by fever sweating high blood pressure
rapid heart rate and increasingly severe muscle spasms throughout the body without treatment
these symptoms can last up to three or four weeks with around 25 percent of untreated patients dying
and even with proper treatment around 10 percent of cases of fatal in the absence of vaccines the
only treatment is supportive care such as the use of muscle relaxants to relieve muscle spasms and
ventilators to support breathing worse still due to the extreme potency of tetanus spasmin
a dose large enough to cause symptoms is typically insufficient to trigger an immune response meaning
that being infected with tetanus typically does not confer lasting immunity to the disease
thankfully in much of the developed world tetanus toxoid or immunoglobulin is readily available and
can be administered either preventatively as a vaccine or reactively within 48 hours of initial
infection for those who are unvaccinated or whose vaccines are out of date in the form of the dtp
vaccine tetanus toxoid is typically administered in six doses throughout childhood and adolescence
with booster shots being required every 10 years in order to maintain immunity rare among vaccines
tetanus toxoid is considered to be nearly 100 effective and thanks to widespread vaccination
efforts annual tetanus deaths worldwide have fallen from 333 000 in 1990 to around 39 000 today
in north america and europe the death toll is only around 70 people per year nearly all among
unvaccinated individuals with the vast majority of tetanus deaths occurring in the developing world
all this brings us back to our initial question can you actually get tetanus from stepping on a
rusty nail as with many old wives tales there is a small grain of truth to this myth albeit
one that neatly demonstrates the classic error of conflating correlation with causation
for while you can indeed catch tetanus from a rusty nail you can just as easily catch it from
a seemingly clean nail for the causative agent is not the rust itself but the clostridium totalized
spores that might be lurking on the nail's surface the supposed causal link between
tetanus and rust stems merely from the fact that a nail or other medical object left outside to
rust is likely also to have been exposed to soil animal feces and other sources of tetanus spores
while the rough rusty surface of the nail provides an ideal hiding place for bacteria and the
perfect vehicle to enter the body if stepped on thus the better advice would be to avoid sharp
metal objects embedded in or even located close to soil but even then you may not be 100 safe due to
their extreme resilience tetanus spores can lurk in all manner of seemingly clean objects including
your own skin and can easily cause infection unless special precautions are taken for example
a handful of people every year are infected with tetanus through contaminated surgical and
dental instruments compound bone fractures and bites from infected animals uses of heroin and
other intravenous drugs are also at high risk of contracting the disease in the past a major killer
of newborn babies was neonatal tetanus usually transmitted through the cutting of the umbilical
cord with a non-sterile instrument if the mother has been vaccinated against tetanus then passive
immunity is transferred to the child meaning that today neonatal tetanus is encountered mainly in
developing countries where vaccination rates are low thankfully as with other forms of tetanus
thanks to concerted vaccination efforts this disease has been largely eradicated in all but
25 countries so in conclusion while thanks to the wonders of modern immunology you are unlikely to
contract tetanus from a rusty nail it's probably still a good idea to avoid stepping on rusty nails
and other sharp metal objects unless you're into that sort of thing and well who are we to judge