Disease surveillance in China is like playing a big game of "Where's Waldo?" to find out where germs and illnesses are hiding.
People who work in disease surveillance are like detectives who are always searching for clues to find out where germs are spreading and making people sick. They look for patterns and trends, and work to figure out how to stop the germs from spreading further.
The detectives watch many different things, kind of like how grown-ups like to watch the news to know what's happening in the world. In disease surveillance, detectives watch the number of people who are getting sick, where they are, what symptoms they have, and how long they have been sick.
One of the ways the detectives keep an eye on people getting sick is by asking doctors and hospitals to report every time someone gets sick with something, kind of like how you tell your teacher when you don't feel well.
Detectives might also look at other things like healthcare stockpiles, which are like secret stashes of instruments or medicines that doctors can use to help people feel better when they are sick.
When a detective finds out that germs are spreading quickly in one place, they might tell the government to take action to stop it, like closing a school so that kids don't get sick from each other, or urging people to wear masks.
Playing the game of "Where's Waldo?" with germs might sound scary, but it's actually really helpful to know where they are hiding so that people can stay safe and healthy.