eli5 if everyone with a certain disease died, would that disease cease to exist?


Say influenza, if tomorrow, everyone with influenza spontaneously died, would the disease cease to exist?

In: 6

Most likely not, because there will be carriers that aren’t affected. That could be other humans who for whatever reason don’t get infected even when they have the virus, or more likely other animals.

Influenza? Probably not as it is transmissible between animals and humans.


In fact many of the worst diseases of the past and currently are related to animals as vectors or reservoirs. Bubonic plague, smallpox, malaria, yellow fever etc etc

It depends on if the bacteria or virus can infect other animals, then all those animals have to be killed too. Bacteria can protect themselves in the form of spores like seeds that will remain dormant pretty much indefinitely until conditions are correct.

Not necessarily. A disease could have a reservoir in non-human animals (influenza for instance can be spread by pigs and birds) or the pathogens might be able to survive dormant in the environment.

In other words, it depends on the disease.

It seems you’re referring to infectious diseases. In which case: no. The pathogen (bacteria, virus, microorganism that causes it) could remain dormant elsewhere.

‘Disease’ is a pretty general term There’s plenty of non-infectious diseases (eg heart disease). That can be caused by deficiencies, or are hereditary, or psychological .