<human>:  What was the mortality rate of the 1918 Avian influenza?
<bot>: The mortality rate was about 5%. The 1918 influenza pandemic was the deadliest pandemic in recorded history, killing more than 50 million people worldwide. The pandemic was caused by a new strain of influenza virus, which was named the H1N1 virus. The virus was highly contagious and spread rapidly around the world. The pandemic was particularly devastating in the United States, where it killed more than 675,000 people.