currently we are going through a worldwide  pandemic everyone is waiting for the pandemic  

to end if we look at the earliest pandemics in  history most of them ended after killing large  

number of people in the affected areas some of  them even ended after there was no one left to die  

with time people learned that taking medical and  health initiatives can halt the spread of these  

diseases and ultimately end the pandemics  in this video i will be talking about four  

deadliest pandemics in history that ended  with major human initiatives and inventions

the first pandemic in the list is the black death  with the death of almost half of the population  

of eurasia in only four years the black death is  considered the deadliest pandemic in human history  

yersinia pestis which most likely originated in  central asia or east asia from there it traveled  

along the silk road and reached crimea by 1347.  the disease was carried by fleas that lived on  

black rats some rats lived in the merchant ships  that spread the disease throughout whole europe  

and north africa the black death resulted in the  deaths of up to 75 to 200 million people without  

any medical advantages and the knowledge of our  rats help spreading the disease there was almost  

nothing to do but by the time people started  to understand that the disease can spread from  

human to human and the way most people from the  infected areas came to the uninfected areas was  

by the ships and more specifically merchant ships  so they came up with the concept of Quarantine  

the word quarantine originated from quarantina  which means 40 days at first it was tarantine  

which means 30 days all the merchant ships that  came from an affected area had to wait 30 days  

in a restricted nearby island to see if any of the  crew members showed any symptoms of bubonic plague  

but the bubonic plague had a 37 day period from  infection to death so in 1448 the waiting time  

was prolonged to 40 days which gave birth to the  term Quarantine the quarantine formula proved to  

be effective it was highly successful  in determining the health of the crews  

so the tradition of current time continued in the  whole europe during future outbreaks although the  

black death already took many lives the 40-day  formula had a great effect in handling the spread  

of the disease through the sea but people still  didn't know how to handle the outbreak on ground  

the privy council of england came up with a  solution of that problem during a plague epidemic  

in london the great plague of london lasted from  1665 to 1666 it was caused by the same disease  

as black death it caused the death of almost 100  000 people in london the previous pandemic black  

death wiped out 75 percent population of london  while the great plague killed 25 percent it was  

a way smaller outbreak than black death but still  it was named great plague because it was the last  

widespread outbreak in london during the 400  years long second pandemic period in europe  

the great plague ended earlier and was the last  major plague outbreak to ever happen in london  

what was the reason behind it well this time  the privy council of england implemented some  

strict rules to control the spread of plague on  ground reports of other places in europe being  

affected began to reach england by 1660. they  applied the quarantine formula before even the  

disease started to spread again all the ships that  came from affected areas had to wait 40 days in  

a restricted island this was pretty effective  to handle the disease on water but if somehow  

the disease reached onshore it could now spread  by humans the privy council of england had to  

do something to control the disease on ground  at first they thought of maintaining hygiene  

at the time london wasn't as safe and clean as it  is now the poorer parts of the city was extremely  

dirty and overcrowded so maintaining hygiene was  almost impossible the privy council then came up  

with something new they introduced the city with  household quarantine they ordered to separate  

the sick people and isolate them in a distant  place far away from other people as the number  

of confirmed cases started to increase they sealed  the houses of infected people and forced them to  

stay inside their homes and all the family members  of the infected person had to carry a white pole  

when they went out in public so that everyone  in the street could maintain distance from them  

some of these rules were cruel but definitely  helped to stop the epidemic in only one year  

while these steps were effective  to slow the spread of this disease  

a major technology was discovered in the 18th  century that could certainly prevent a disease  

vaccine one of the most important discovery  in human history while the actual vaccine  

was discovered in 1796 the chinese people started  practicing a similar method from the 16th century  

and all of this started to prevent a disease  called smallpox an infectious disease that caused  

several outbreaks in different times all over the  world the origin of smallpox is unknown earliest  

evidence of the disease dates back to the 3rd  century bce in egyptian mummies the risk of death  

after contracting the disease was about 30 percent  in 18th century europe almost 400 000 people  

died from this disease every year and in last  hundred years of its existence it killed almost  

500 million people worldwide the chinese people  started practicing variolation in the 16th century  

it is the oldest method of inoculation that  could create a strong immunity against smallpox  

this technique used dried scabs that was  collected from a mild smallpox patient  

dried scabs were grounded into powder and puffed  up into the patient's nostril this would cause a  

mild infection the variolated patients showed  same symptoms as the actual infected patients  

it took two to four weeks to cure but after fully  recovering the variolated patients would acquire a  

strong immunity against smallpox there are hints  that ancient indians used to practice a similar  

method but there is no ancient sanskrit script  that supported this theory in the year 1700 an  

employee of the east india company stationed in  china sent a report to the royal society of london  

describing this old method of variolation but  no action was taken later india and middle east  

started to practice variolation and through the  ottoman empire violation reached europe although  

this method was effective to prevent smallpox  this wasn't fully safe the variolated patients  

still had a two percent risk of death but this was  a way better option compared to a 30 risk of death  

with the naturally acquired smallpox besides it  was the only option for people until 1796 when  

the british doctor edward jenner demonstrated that  an infection with a relatively weak cowpox virus  

could create immunity against smallpox virus  he inoculated james phipps the eight-year-old  

son of his gardener with material taken from a  cowpox patient after six weeks jenner inoculated  

james with smallpox to check if he was immune to  smallpox and it worked he had no effect the boy  

was immune to smallpox although a safer version  of the smallpox vaccine was discovered later  

edward jenner is still considered the founder  of vaccinology it took a long time to vaccinate  

most of the people on earth in 1980 the world  health organization announced that smallpox had  

been completely eradicated from the face of the  earth before moving forward if you appreciate our  

effort on making this video then please like the  video and don't forget to hit the subscribe button  

the last pandemic in the list is the cholera a  disease caused by the bacteria vibrio cholerae  

the first cholera pandemic originated in india in  1817 and spread across whole world causing seven  

major pandemics in last 200 years primary symptoms  of the cholera patients are watery diarrhea and  

liquid vomiting without any treatment the patient  can produce 10 liters of diarrhea a day and due to  

dehydration the patient can die within a few hours  cholera normally spread by the contamination of  

water and food like other infectious diseases the  transmission of cholera was a mystery back then  

most of the scholars at the early 19th century  believed in the miasma theory according to  

which diseases like cholera and bubonic plague  were caused by a bad air called miasma english  

physician John Snow was one of the few scholars  who didn't support this theory by his previous  

research John Snow believed that cholera spread by  the contamination of water and during the cholera  

pandemic in london he got a way of demonstrating  that contaminated water was actually the source of  

cholera in 1854 an outbreak killed many people  in a neighborhood in london called soho snow  

studied all the records of soho very deeply and  found out that most of the people who died lived  

near a broad street water well he suspected the  water was contaminated with some more information  

snow was able to convince the local officials  to close the broad street drinking well  

and soon cholera attacks on soho diminished snow's  work was a breakthrough in public health research  

although officials weren't convinced immediately  but in future when the germ theory established  

developed countries started to emphasize  the protection of water from contamination  

and a secure sewage system although cholera  is eradicated in the developed countries  

some developing and undeveloped nations are  still dealing with cholera due to contamination  

of water by poor sewage system thank you  for watching the video if you enjoyed like  

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