The — flu pandemic , also known as the Great Influenza epidemic or by the common misnomer Spanish flu , was an exceptionally deadly global influenza pandemic caused by the H1N1 subtype of the influenza A virus. The earliest documented case was March in the state of Kansas in the United States, with further cases recorded in France, Germany and the United Kingdom in April. Two years later, nearly a third of the global population, or an estimated million people, had been infected in four successive waves.
Estimates of deaths range from 17 million to 50 million, [ 6 ] [ 7 ] and possibly as high as million, [ 8 ] making it one of the deadliest pandemics in history. The pandemic broke out near the end of World War I , when wartime censors in the belligerent countries suppressed bad news to maintain morale , but newspapers freely reported the outbreak in neutral Spain , creating a false impression of Spain as the epicenter and leading to the "Spanish flu" misnomer.
Most influenza outbreaks disproportionately kill the young and old, with a higher survival rate in-between, but this pandemic had unusually high mortality for young adults.
The Spanish flu was the first of three flu pandemics caused by H1N1 influenza A virus ; the others being the Russian flu and the Swine flu pandemics. This pandemic was known by many different names—some old, some new—depending on place, time, and context.
The etymology of alternative names historicises the scourge and its effects on people who would only learn years later that invisible viruses caused influenza. Clinical indications in common with the pandemic included rapid symptom progression to a "dusky" heliotrope cyanosis of the face. This characteristic blue-violet cyanosis in expiring patients led to the name 'purple death'. The Aldershot physicians later wrote in The Lancet , "the influenza pneumococcal purulent bronchitis we and others described in and is fundamentally the same condition as the influenza of this present pandemic.
