It didn’t, there were several so-called echo epidemics after that one. Later on, the disease did reoccur locally, with varying degrees of intensity

Varying degrees of intensity? There are branches of severity in the Black Plague?

People get infected by it in the present day.

Antibiotics help a lot, and we didn’t have those in the 1300’s.

As for why the full intensity didn't reoccur: the Black Death killed a third of the people in Europe (for comparison, that's about 100x the death rate of covid in the US), and infected most of the rest. By killing off the most vulnerable parts of the population, it made Europeans particularly resistant to plague, so future plague epidemics were less bad. It's similar to how modern Native American populations are no longer ravaged by diseases that, when their ancestors were first exposed to them, wiped out as much as 90% of the population.

Yes. Not everyone who got the plague died, although a large percentage did (plague is fatal ~half the time without treatment), and there can be different degrees of spread for a particular plague epidemic.

The main reason for the end of the black death was the implementation of successful Quarantines that allowed pockets of infection to burn themselves out.

But it didn't disappear overnight, numerous smaller local outbreaks continued for a long time after.

Improvements in overall hygiene, sanitation, and dealing with the rats is what eventually got rid of the Black Death for good.

Although it is still around today, just very uncommon. Modern anti-biotics and sanitation is what prevents it from being a problem.

Another working theory is that the Black Death killed off so much of the European population that those that remained living were the ones that had a degree of immunity or were more naturally resistant.

People either died or became immune. Eventually, plagues burn themselves out, running out of new people to infect and being eliminated in the bodies of both the survivors and the victims.

Literally HOW DO YOU BECOME IMMUNE TO THE BLACK PLAYUE

You get it and live. It was not 100% fatal.

Additionally, if, say, 10% of the population is naturally immune, and you wipe out a third of the population overall with the disease, you end up with 15% of the survivors being naturally immune.

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Some strains of the bacteria aren't as deadly, and some aren't as good at infecting new people. Some are too deadly and kill people very quickly before they can infect a bunch of other people. The Plague bacteria actually still exists today and there are minor outbreaks every now and then even now, although they are extremely rare in countries with widespread access to antibiotics.

The black death, was a plague spread by the bacteria Yersinia Pestis, many people died of the disease the remaining population were immune or resisted the infection so there were no new hosts for the disease. https://youtu.be/aoCDoUpTfTw

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You become immune by surviving the disease. For some they will show no symptoms and it seems like they were always immune. Many will develop symptoms of varying severity and survive the infection. Now they have some immunity to the disease.

You either survive and gain immunity or die.

Just by observation.

Even without germ theory per se, back as far as ancient China, Mesopotamia, and Egypt, people could tell that exposure to SOMETHING caused disease. Night air? The moon? Miasma? Insect bites?

Keeping the sick away from everybody else, and noting that people got sick around sick people doesn't require the direct knowledge that micro-organisms are responsible.

Yes. Both intensity of the illness, and intensity of the outbreaks.

Like everything else. You get it, and survive.

Also, plague did mutate, and morphed through history. When people got bitten by fleas it wasn't as deadly (still bad) as when transmission person to person (by coughing) became possible.

Like everything else. You get it, and survive.

Also, plague did mutate, and morphed through history. When people got bitten by fleas it wasn't as deadly (still bad) as when transmission person to person (by coughing) became possible.

Trial and error

They discovered that people who kept clean didn't get as sick

The Pope famously hid in a circle of flame to keep him safe during the worst of the plague. The theory was to keep 'bad air' away, but in fact it was keeping him safe from the rats

There are actually three types of Plague, all from the same bacteria. The most common one, Bubonic Plague infects the lymph nodes, but it can be airborne as pneumonic plague as well. The most serious form is septicemic plague, which is the lease common because you generally die within 24 hours of symptoms presenting without massive doses of antibiotics

there is a difference between the normal one and the one in the lungs (that's 99% lethal).

The intensity depends on two other factors:

1. response of local authorities (which over the course of the centuries became more adept at dealing with outbreaks: one such measure was quarantaining (The Venetians had an island for that), ships using special flags to signal the disease on board, etc. The duke of Milan infamously bricked in any house that had a patient in it: harsh but it worked.

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2. the health of the population: as mentioned before, resistance did improve in the population, HOWEVER: famines (either due to war or bad harvests) impacted the health of the population that was affected by an outbreak.

that would be a stretch to say that Europeans in general got more resistance. The mutation offering more protection or even immunity did significanly spread in the gene pool, that is true. However, that would fail to explain why the outbreak in London (to give an example) in 1666 claimed so many dead.

If I recall correctly it is estimated that about 90% of the native american population died because of unknown diseases. However, some of those became endemic later on. Plague didn't (nor did that other scourge: smallpox). Plague is therefore one of those diseases that IF found by a doctor, must be reported to the national health authorities almost immediatly (as: within 24 hours) in my country.

The 1348 outbreak coincided with a period of bad harvests and relative overpopulation. Resulting in lower resistance among the populace. It was, in the words suitable for a five year old: a double whammy

It didn't disappear.

There have been multiple smaller outbreaks since then, and one major pandemic in the mid-1800s.

The last plague oubreak in the US was in Los Angeles 1924-1925. Killed about 30 people.

The reason the plague ended was that people stopped spreading it. Successful implementation of quarantines is largely credited with depriving the disease of new human vectors. That, and it had already killed a third of Europe and basically burned through most of the susceptible population. It's harder for a pandemic to spread when the population density has dropped that much.

ETA: You can still catch a Yersinia pestis infection today if you really want to. Go hang around with the wrong rodents in, e.g., the US Southwest. A couple in Mongolia recently died of Plague after eating the wrong marmot.

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> double whammy

No whammy, no whammy, no whammy. Aww damn, plague

Was the rats thing not recently called into question?

Rats were likely not the culprits, rather it was lice spreading from human to human.

https://www.bbc.com/news/science-environment-42690577

> "The conclusion was very clear," said Prof Stenseth. "The lice model fits best."

> "It would be unlikely to spread as fast as it did if it was transmitted by rats.

> "It would have to go through this extra loop of the rats, rather than being spread from person to person."

Once a blood-borne infection is sufficiently common, it doesn't matter which little biting parasite is carrying it. It may have jumped from rat-flea-human to human-louse-human transmission.

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Vaccines kinda undercut that.