Spanish flu

The 1918–1920 flu pandemic, often called the Great Influenza epidemic or, misleadingly, the Spanish flu, was a devastating global outbreak caused by the H1N1 influenza A virus. The first likely cases appeared in March 1918 in Haskell County, Kansas, with additional cases recorded in France, Germany, and the United Kingdom the following month. Within two years, roughly 500 million people—nearly a third of the world’s population—had been infected. Death toll estimates vary widely, from 17 million to 50 million, and possibly as high as 100 million, ranking it among history’s deadliest pandemics.

The pandemic emerged near the end of World War I. Wartime censors in combatant nations suppressed negative news to preserve morale, but neutral Spain’s newspapers freely reported the outbreak, creating a false impression that Spain was the epicenter. This led to the name “Spanish flu.” Limited historical data make the pandemic’s true geographic origin uncertain, with competing theories about its initial spread.

Unlike most flu outbreaks, which disproportionately kill the very young and very old, this pandemic saw unusually high mortality among young adults. Scientists have proposed several explanations, including a six-year climate anomaly that altered disease vector migration and increased spread via waterways. However, the claim of high young-adult mortality has been disputed. World War I worsened malnutrition, overcrowding in medical camps and hospitals, and poor hygiene, which promoted bacterial superinfection—killing most victims after a typically prolonged deathbed illness.

The pandemic was known by many names, varying by place, time, and context. These names reflect the era’s lack of scientific understanding—people would only later learn that viruses caused influenza. In July 1918, the Sierra Leone Weekly News suggested a biblical framing, quoting Exodus 16: “One thing is for certain—the doctors are at present flabbergasted; and we suggest that rather than calling the disease influenza they should for the present until they have it in hand, say Man hu—‘What is it?’”

Outbreaks of influenza-like illness were documented in 1916–17 at British military hospitals in Étaples, France, and Aldershot, England. Clinical signs common to the 1918 pandemic included rapid progression to a “dusky” heliotrope face. This blue-violet cyanosis in dying patients earned the name “purple death.” Aldershot physicians later wrote in The Lancet that the purulent bronchitis they described in 1916–17 was fundamentally the same condition as the pandemic influenza. This bronchitis has not been linked to the same A/H1N1 virus but may be a precursor. In 1918, the illness was called “epidemic influenza,” “the grip” (from French *la grippe*), or “three-day fever” in Kansas and Spain.

Many alternative names were exonyms, reflecting a pattern of making new diseases seem foreign. Before the 1889–1890 pandemic (the “Russian flu”), Russians called it “Chinese catarrh,” Germans called it “Russian pest,” and Italians called it “German disease.” These epithets were reused in 1918, along with new ones.

Outside Spain, the disease was soon misnamed “Spanish influenza.” On 2 June 1918, *The Times* of London ran a dispatch from Madrid titled “The Spanish Epidemic,” reporting over 100,000 victims of “the unknown disease…clearly of a gripal character.” Three weeks later, *The Times* noted that “everybody thinks of it as the ‘Spanish’ influenza to-day.” Three days after that, an ad for Formamint tablets appeared, promising to prevent “Spanish influenza.” When the outbreak reached Moscow, *Pravda* announced “Ispánka (the Spanish lady) is in town,” making “the Spanish lady” another common name. The outbreak did not originate in Spain—only the reporting did, due to wartime censorship. Spain, neutral and unconcerned with combat readiness, had no propaganda machine to suppress news, so its newspapers freely reported the epidemic, making Spain appear the locus. The censorship was so effective that Spanish health officials were unaware neighboring countries were similarly affected. In an October 1918 “Madrid Letter” to the *Journal of the American Medical Association*, a Spanish official protested: “we were surprised to learn that the disease was making ravages in other countries, and that people there were calling it the ‘Spanish grip’. And wherefore Spanish? …this epidemic was not born in Spain, and this should be recorded as a historic vindication.”

Other exonyms included “American flu” in the French press, later dropped to avoid antagonizing an ally. British soldiers called it “Flanders flu,” German soldiers “Flandern-Fieber” (Flemish fever), both after a Belgian battlefield. In Senegal it was “Brazilian flu,” in Brazil “German flu.” In Spain it was also known as “French flu” (*gripe francesa*) or “Naples Soldier” (*Soldado de Nápoles*), after a popular zarzuela song. “Spanish flu” (*gripe española*) is now common in Spain but remains controversial.