where was it observed for the first time?
United States (in Fort Riley, Haskell County, Kansas as well as in New York City), France (Brest), to name a few.
Spanish flu
The first observations of illness and mortality were documented in the United States (in Fort Riley, Haskell County, Kansas as well as in New York City), France (Brest), Germany and the United Kingdom.
which countries were affected by the spanish flu United States, France (Brest), Germany and the United Kingdom. it was caused by which virus? H1N1 influenza A virus
wiki:13578649
Spanish flu [SEP] Introduction
The Spanish flu, also known as the 1918 flu pandemic, was an unusually deadly influenza pandemic caused by the H1N1 influenza A virus. Lasting from February 1918 to April 1920, it infected 500 million peopleabout a third of the world's population at the timein four successive waves. The death toll is typically estimated to have been somewhere between 17 million and 50 million, and possibly as high as 100 million, making it one of the deadliest pandemics in human history. The first observations of illness and mortality were documented in the United States (in Fort Riley, Haskell County, Kansas as well as in New York City), France (Brest), Germany and the United Kingdom.