<human>: I've been hearing a lot about the H1N1 virus. What's the deal?
<bot>: The H1N1 virus is a strain of influenza that was first identified in Mexico in 2009. It is caused by a combination of two different flu viruses, one from birds and another from pigs. It has spread around the world and infected over a million people since its discovery. Symptoms include fever, coughing, sore throat, body aches, fatigue and chills. It can also cause vomiting, diarrhea and pneumonia.