In 2009, there was a sickness that spread around the world. One of the places where it started was in Mexico, a country in North America. This sickness was called the flu, which stands for influenza.
Flu is caused by tiny things called viruses. These viruses can make people feel very sick. They make your body hot, give you a bad cough, and make your nose run. The flu virus can spread from person to person when someone coughs, talks or sneezes.
When the Mexican people started feeling sick, many of them didn't know what was happening. Some people were so sick that they had to go to the hospital. Doctors and scientists started studying the sickness to try to find out what was causing it and how it could be treated. They found out that it was a new type of flu virus that no one had seen before.
Governments around the world started working together to try to stop the flu from spreading even more. They told people to stay home if they felt sick and not go to school or work. They also said that it was important to wash your hands all the time and to cover your mouth and nose when you cough or sneeze. These small actions could help stop the flu from spreading from person to person.
Although many people around the world got sick from this flu, most people were able to recover. Scientists were able to create a vaccine, which is a special medicine that can help protect you from getting sick with the flu. People around the world are still working hard to stop the flu from spreading, and to make sure that if it does once again, we are ready to fight it.