6 Diseases That Have Shaped Human History

Infectious

diseases

have

had some pretty major impacts on

human

history

, and to put it mildly, take the Black Death of the Middle Ages, which wiped out more than a third of Europe's population, or smallpox, which traveled to America. on ships and decimated the natives. As a people, we've been hunted by microbial enemies, but sometimes our drive to understand them has laid the foundation for modern science, so here's a look at six of the most devastating

diseases

in

history

and how they affected us in some pretty big ways. We'll start our list with the plague. Caused by the bacteria its sania pestis is transmitted to people when they are bitten by fleas carried by rodents, most famous for the 14th century outbreak called the Black Death, the bacteria actually caused three different forms of the disease from which probably

have

heard of more frequently.

A common bubonic plague is when these bacteria attack the lymphatic system, which helps protect the body from garbage-like toxins. Between two and six days later, infected victims have a high fever, headaches and vomiting, and are also They inflame the lymph nodes called buboes, which gives the plague its name. Bubonic plague causes a lot of damage on its own, but if left untreated it can develop into another form, although these types can also occur on their own. If bacteria infect the bloodstream, called septicemic plague, they can cause clots that prevent blood from reaching the tissues. They turn black when they die or if the germs infect the lungs, it is called pneumonic plague, this can cause coughing up blood and rapid death and allows people to transmit the plague through small droplets in the air.

Nowadays, all forms of plague can be treated with antibiotics, but they used to kill half or more of the infected patients, which had enormous effects on society, the first confirmed plague epidemic was called the Plague of Justinian. and devastated the Roman Empire from the year 541 C II and contributed to its fall in the Roman capital of Constantinople. It is estimated that at its peak more than 5,000 people died per day the second great wave reached Europe in 1347 when merchant ships arrived in Italy full of six sailors the black plague devastated the continent in just a few years and during that time it is estimated that a quarter to a half of all Europeans died some 25 million people over the next two centuries the plague continued to appear and the first quarantines were implemented at the time when infectious diseases were thought to be transmitted by contaminated air, So officials tried to isolate the sick and those traveling from places that had an outbreak to prevent more deaths, and although the science was wrong, quarantines helped prevent the spread of pneumonic plague among people and control rats. with fleas carrying the plague bacteria.

The last major wave of outbreaks began in 1894 in rural China that swept across Asia and Australia, and eventually, after a few decades, scientists discovered the bacteria and carriers behind it all, allowing us to begin eliminating this disease. Smallpox was also a leading cause of death in the past, killing nearly 30 percent of all people who suffered from it. disease caused by the variola virus that begins with a high fever and headache, then small lumps filled with infectious fluid appear everywhere. Those are smallpox and in survivors they eventually scab over and turn into scars. Humans infected each other through small droplets coughed or sneezed into the air. but in a super gross twist, the smallpox fluids and scabs spread all over the clothes and blankets and were also able to infect new hosts.

Now smallpox was devastating for much of

human

history, but it hit especially hard when settlers from Europe invaded the Americas, native populations had immunity. systems that were adapted to combat local diseases, not foreign ones, so the variola virus infected and killed large numbers of them. General diseases such as smallpox may have killed up to 90% of the Native American population. Smallpox probably helped the Spanish conquer the Aztecs. The empire also, although not on the same scale, European settlers were also affected by the disease, as some estimates think that George Washington lost more troops due to the smallpox epidemic from 1775 to 1783.

Casualty rates in the Revolutionary War they improved a little after a large army. Variolation or intentionally infecting people with a bit of gunk from a patient's scabs to hopefully help them develop immunity. Exposing people to the virus in a controlled way ended up being safer than usual, but they still suffered some symptoms and there was a risk of death later. Doctors tried to make it less dangerous by using people or animals infected with cowpox, a less harmful cousin of smallpox caused by the vaccinia virus. This process was called vaccination and led to the eradication of smallpox and all the vaccines we depend on today. diseases that crossed oceans, let's talk about syphilis, scientists believe that this sexually transmitted bacterial infection may have reached Europe in settlers returning from America.

It is caused by the bacteria Treponema pallidum and the initial symptoms are not fun, rashes, sores, fever, headaches and muscle aches. It is transmitted by direct contact with the sores or is transmitted from an infected mother to her child after a few weeks or months, although the rashes and sores disappear and the disease passes into a latent stage where it can be detected in a blood test. , but not. It does not cause any symptoms and in up to a third of untreated cases the disease recurs causing dementia, multiple organ dysfunction, much pain and death. The first recorded outbreak of syphilis began in 1495 after a French army victory celebration with infected sex workers, so people at the time started calling it the French disease and it was quite deadly, possibly because the disease was new to Europe and people did not have any immune resistance to it.

It's hard to say how many people syphilis killed because there was no medical record tracking the cause of death, not to mention that sexually transmitted infections were considered embarrassing, so many people tried to hide them or pass them off as other things like leprosy, what we do know is that the disease devastated the world until one of the first antibiotics developed to put an end to it at the beginning of the 20th century, immunologist dr. Paul Ehrlich had discovered that certain dyes only bound to specific types of cells in his laboratory. His discovery led him to believe that certain compounds could attack disease-causing agents such as bacteria without attacking healthy tissues, a treatment that would later be called chemotherapy through systematic screening. process Ehrlich found a chemical that he developed into an antisyphilitic drug called Solverson.

It quickly became the most prescribed drug in the world and the process that led to its discovery earned Ehrlich the Nobel Prize in Physiology or Medicine in 1908 caused by a bacteria called Vibrio. cholerae cholera is a serious gastrointestinal disease that causes vomiting and diarrhea as early as 12 hours after infection, these bacteria produce toxins that bind to enzymes in the small intestine that control the secretion of water from the rest of the body, specifically the toxin causes these enzymes to flood the intestines with water. and that leads to dehydration so severe that it is fatal. There were reports of similar diseases in India as early as 1000 CE II, but cholera did not become a global problem until the 19th century, when widespread trade began to occur.

Cholera caused a lot of fear everywhere. disappeared and even today it is a public health problem with millions of estimated cases per year and one hundred thousand deaths. Today we know that cholera is transmitted through drinking water that has been contaminated by infected excrement particles, so when it arrived in England in the 1830s, the medicine was discarded. by the idea that diseases, whether the Black Death or cholera, were caused by air contaminated by the corpses of impure people or even swamps, so in 1854, when a doctor named John Snow traced almost all the victims of a cholera outbreak in London down to a single water pump, no one really believed him.

City officials removed the handle from the pump that prevented people from drinking that water to please him and new cases of cholera decreased dramatically, but people still didn't believe his ideas until a local minister set out to prove him wrong and that failed spectacularly in his The report actually ended up tracing the outbreak to a dirty diaper of a baby who had contracted cholera on the outskirts of London. . Snow's revolutionary methods for tracking infection patterns and finding the source of an outbreak is why he is considered one of the fathers of modern epidemiology, so it turns out John Snow might have known something after all. , mosquitoes are a well-known pest when it comes to spreading.

The disease and yellow fever is no exception, it is a viral infection and most people infected with flavivirus experience symptoms such as fever, chills, aches, fatigue and vomiting. An unfortunate 15% or so of patients suffer much worse, with bleeding jaundice and multiple organ failure that can lead to death. Today we have a vaccine for yellow fever, but that was not the case in the 1880s, when the French began building the Panama Canal. We knew yellow fever existed, but not how it was transmitted, so we couldn't prevent people from getting sick. More than 20,000 workers died of yellow fever or malaria or a funny combination of both, so the French abandoned construction in 1889.

It wasn't until the 20th century that we discovered that mosquitoes were to blame and that the United States was able to combat the disease and finish the canal they drained puddles of water near towns and houses, which is where mosquitoes lay their eggs, and they covered the water that they could not drain with films of oil to suffocate the larvae that had already hatched, and they threw pesticides everywhere trying to kill them. to all the mosquitoes, they were able to find that the last disease on our list is a little different from the others, it is not transmitted, it is inherited and that is why it used to be called a royal disease.

Hemophilia is a disorder that makes it difficult for blood clots to form, causing victims to bleed to death. of minor wounds that humans would normally seal have 20 different proteins that help form blood clots, but hemophilia is caused by problems in only two and both genes involved are on the that you have two copies of each gene plus a 23rd pair which is usually XX or of a widow on the other hand, it takes two copies to express itself, so people can have only one copy, not express the trait, and still pass it on to their children.

They are called carriers. Now recessive traits on sex chromosomes may work a little differently because they are not necessarily identical. people who are XY do not have a backup copy of any of the gene sets, so recessive diseases caused by genes on the Being pure blood, the royal families of Europe were famous. for incest and two related people have a higher chance of both being carriers of the same recessive trait because they share more genes than unrelated people Queen Victoria of England was a carrier of hemophilia and one son and three grandchildren bled to death from minor injuries at the beginning of adulthood the most famous of his dangerously bleeding descendants was the Russian prince Alexei Romanov.

The Romanov family kept the illness a secret from their only heirs so as not to appear weak and relied on the so-called magical healing abilities of the Siberian Grigori Rasputin. The perceived influence that Rasputin had. about the royal family created tension with the general public and may have hastened the execution of the royal family in 1918 during the Russian Revolution, so perhaps recessionary disorders are the reason why the Lannister and Targaryen tsars ruined both the perceived influence that Rasputin had over the royal family. generated tension with the general public and may have hastened the execution of the royal family in 1918 during the Russian Revolution, so history is

shaped

by many forces, especially things like human health, these six diseases caused widespread deaths, changed societies and revolutionized whatwe know. about medicine in ways that still impact us today thank you for watching this episode of scishow which is complexly produced by a group of people who believe that the more we learn, the better we do as humans, if you want to learn more about the human health, check out one of our sister healthcare rating channels on youtube.com reduce healthcare rating