<human>:  When did the 1918 Avian influenza start and when did it end?
<bot>: The 1918 flu started in the spring of 1918 and lasted until the fall of 1918. It was a very deadly pandemic that killed millions of people worldwide. It was caused by a virus that was a new strain of influenza that had never been seen before. It was a very deadly virus that caused severe pneumonia and respiratory problems.