Imagine a big ocean current getting really warm, like taking a bath that's too hot!
This warm current can change the weather all over the world, and that can make a kind of sickness called cholera spread more easily.
Scientists looked at a really bad cholera outbreak a long time ago and saw that it happened around the same time as a warm ocean current.
They say that watching the weather and how germs change is important to keep people safe from cholera!
