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Meta-logistics for the author The problem that you — as the author — have is this: how do you kill off 95% of the world's population by means of a plague, without having the corpses cause so much health problems that you drag down the remaining 5% too? The answer is: you do not. It is not credible to kill 19 in 20 people and then have the remainders live ...


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Natural Vaccination. Read about how Cowpox was used to vaccinate against Smallpox, this is our IRL first instance of vaccination against a disease. The word “vaccination,” coined by Jenner in 1796, is derived from the Latin root vaccinus, meaning of or from the cow. Once vaccinated, a patient develops antibodies that make them immune to cowpox, but they ...


85

If you have European blood in you, are aged between 19 and 45 and are physically fit, the chances of you being brought down by the plague would be very little. Read this Scientific American article for details. Also this livescience article states that the pandemic altered the genes of European people. The Europeans who survived the plague developed ...


78

Because some self-proclaimed health guru claims that it's good for you to have that disease. The miracle-virus causes your body to absorb free cosmic energies. Your constantly raising body temperature is proof that it works. The headache you feel is because your brain is reconfiguring itself to become more effective. When the process is over, you ...


77

While distilling leaves you with absolutely clean water, it is very costly. The constant need of burning material is a real problem if a bigger amount of water is required. But fortunately, there is another method that is way cheaper. Filtering: Every citizen can build his own water filter, with gravel, sand, charcoal and some cloth: This filter clears ...


76

The horses cannot be domesticated You say... It is useful to my story line to eliminate horses as a mode of fast travel Well then, that is easy. In your alternate world... Horses have the temperament of and a (lack of) family structure like zebras. This video by CGP Grey explains the matter simply: Zebra vs Horses: Animal Domestication Horses ...


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This is going on on Earth even as we speak! We're talking about ... Ideas. They are spread through social contact, some prospective hosts can fight them off, but some succumb and spread them further. Examples: Memes Multi-level marketing recruitment Philosophical movements (planned and unplanned). You've heard of a civilization going through a malaise; ...


64

There are three forms of the plague, bubonic (famously from fleas), septicemic (as much from other infected people, like those with bubonic plague) and pneumonic (also from other infected people). If you're going to catch the plague, catch bubonic plague, the others will kill you within 24/36 hours respectively. With bubonic plague you actually have a ...


62

She would likely need a full round of vaccinations, just like everyone else in the modern world. If anything modern sanitary conditions would be less likely to spread diseases to her. I would personally be more concerned about her starting new outbreaks of diseases here that had been effectively eradicated and are no longer generally vaccinated against. ...


57

Pre-emption is the best prevention There is no way to do it with 15th century technology. But. The best course of action is to pre-empt the epidemics by running them early. Use your time traveling saucer to kidnap some flea-infested bug-ridden mangy European and Chinese serfs in the 5th century, and drop them in the Americas. The epidemics will start, lots ...


50

Stopping the plague? No. However, if he could somehow convince enough rulers and authoritative persons that the plague is carried by fleas (Xenopsylla cheopis) abandoning dying and dead rats (mostly Rattus rattus) and biting people, he might be able to reduce the death toll from tens of millions to tens of thousands. He wouldn't need to explain that the ...


49

Yes, but not in the way you are thinking. One way this could happen is if some killer fungus starts growing unchecked throughout the planet, on land and sea. By killing all plant life it would destroy every other ecosystem, so it would wipe out all mammals. It would also practically wipe out all other members of the animal kingdom. This is part of the plot ...


48

An infection suddenly becoming lethal after infecting a majority of the population is pure fiction. The closest real world analogue are diseases that have an asymptomatic infectious phase before they start harming people. Unlike in Plague inc. where every infected person suddenly gets ill, real diseases don't coordinate between people.


47

There are many, many diseases that require 'maintenance drugs': Heart disease Requires beta blockers, diuretics, statins for cholesterol management. Risk of death due to heart attack or stroke is elevated, but not predictable - but if you take beta blockers and then stop them abruptly, then the results can be very serious. Diabetes Requires insulin ...


45

The most egregious break from reality in Plague-Inc is that every pathogen around the globe suddenly mutates from harmless to lethal at the same time. This is not how real-world diseases work. When there is a mutation, that's actually a new disease which evolves locally in one place and then spreads from there. Anyone infected with the old strain won't ...


39

This kind of culture is not unheard of. The most well known (at least to me) is the Fore tribe of Papua New Guinea. As part of their funerary rights they eat the brains of the deceased. This tradition led to Kuru, an endemic degenerative brain disease. If this tradition were more wide spread there are ways it could (health wise) work and ways it would ...


39

An excuse to avoid something worse The virus could be a valid excuse for anyone not wanting to go to war or being involved in a forced marriage.


38

Believe it or not, there are people who purposefully seek to be infected with HIV. These people are referred to as "Bugchasers". Lethality: Well, HIV doesn't kill you directly, and those with HIV have near normal lifespans with proper treatment: http://www.bbc.com/news/health-39872530 cited study: Survival of HIV-positive patients starting ...


37

Inoperable cerebral aneurysm. Whilst not specifically fitting some definitions of "disease" such as "caused by an invading pathogenic organism": Having a variety of potential causes - heredity, trauma, abnormal vascular developement, high blood pressure. These can occur in inaccesable parts of the brain like a little time bomb which can rupture and kill ...


36

There are many issues that arise. The body is not designed for high pressures. As an example, as you go lower, you have to breathe air which has a smaller and smaller concentrations of oxygen. This is because if the partial pressure of oxygen rises too high (1.4-1.6atm), it becomes toxic and kills you. There's nitrogen narcosis. Nitrogen has a narcotic ...


36

The Vampire Virus is ferociously territorial. However, another immune cell specialises in killing cells that have a reduced number of MHC class I molecules on their surface – this cell is a natural killer cell or NK cell for short. When the NK cell finds a cell displaying fewer than normal MHC molecules it releases toxic substances, in a similar ...


35

Yes it is possible. No, it is not going to be cheap. It was done with West Berlin until 1989. Place heavily armed check points on all the road, with all the necessary to forcefully stop any vehicle trying to past them. If you have been to LAX airport car rental, you know what I mean Set patrolling of the border where no roads are present. You can also mine ...


34

Convince everybody the plague is spread by rats. You know what causes the plague. It's caused by fleas carried by infected rodents, or by inhaling pathogens exhaled by infected individuals. The most effective way you have of surviving the plague is making sure that everybody else in the world knows this as well. Try to convince them that you have authentic ...


34

Anything that isn't cancer. You seem to describe something known as biological immortality, which occurs when an organism cannot simply die of old age. Lucky, a jellyfish species called Turritopsis dohrnii has this condition. Let's talk about what kills them. Pathogens Even if death from old age cannot occur, microbes can kill the body. Viruses may be out ...


34

You need a virus that starts to be contagious early, but give the full spectrum of symptoms late. If your virus is fast to act, it will be caught in quarantines and studied. If you want pandemic scale event, you need it to spread "disguised" as common cold or something equally innocent, and only kick in when it's already too late and substantial portion of ...


32

Based on some handy data from 2011, we can estimate worldwide deaths at around 55 million per year. At that rate, for 700 million people to die, you’d only have about 12.65 years. Now, this annual death toll is definitely going to see some yearly variance based on current world conflicts, epidemics, natural disasters, etc. In general, I would not expect ...


32

Quorum sensing. This concept pretty much is defined by the question. An organism behaves in one way at low population densities, but then switches to an alternative mechanism once they reach higher densities. This is usually done using a chemical trigger upon reaching high population densities. While this system only works on relatively short ranges in ...


30

You can't ask "how long" in years, but in generations. And the answer is One Generation. We have two kinds of immunity... innate immunity and acquire immunity. The first one (innate immunity) will react to a multiplicity of organisms. And it will react always the same way. This is the first line of defense of your organism, because it's the simplest and ...


30

Amadeus's answer is good and covered one of the scenarios I was going to suggest. Here's the second. In the early twentieth century, before antibiotics, patients with tertiary syphilis were intentionally infected with malaria to induce a fever; this was called malariotherapy. https://en.wikipedia.org/wiki/History_of_malaria#Malariotherapy Malaria was ...


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