The forgotten flu

The Spanish flu,also known as La Grippe,was a pandemic that struck the world in 1918-19 and affected the US,Europe,Asia,Africa and parts of South America,by some accounts infecting a fifth of the world. The passage of the disease was greatly aided by the travel made necessary by World War-I. Despite its name,the Spanish flu is widely acknowledged as first rearing its head as an epidemic in America,although there is speculation it may have originated in China. It is believed that the pandemic earned its monicker due to the high number of mortalities in Spain,as well as the fact that most reliable news of its spread came from the country,which had less censorship due to its neutral status during the war.

How did it spread?

The flu hit the world in three waves,the second being far deadlier than the first and third. In the first wave,which began around March 1918,the flu seemed relatively harmless and affected the elderly and already ailing rather than the young and healthy. About five months later,the trend changed,as the virus had apparently mutated and become more deadly the war may have had a part to play in this,as instead of staying home,sick soldiers continued to fight in trenches and go to overcrowded hospitals. This also considerably lowered the age of fatalities as the soldiers and their acquaintances were most likely young adults.

How many died?

While the exact figures remain elusive,it is believed that between 10 and 20 per cent of the afflicted lost their lives. According to a paper,1918 influenza: the mother of all pandemics,published by the US Center for Disease Control CDC,An estimated one-third of the worlds population or 500 million people were infected and had clinically apparent illnesses. The disease was exceptionally severe. Case-fatality rates were more than 2.5 per cent ,compared to less than 0.1 per cent in other influenza pandemics. Total deaths were estimated at 50 million and were arguably as high as 100 million.

How did it end?

The pandemic ended almost as abruptly as it began,with new cases declining to almost nothing by the end of 1918. In his book The Great Influenza: The Epic Story of the Deadliest Plague In History,author John M Barry suggests that the virus quickly mutated to a less lethal strain,which is a usual occurrence as viruses tend to become less deadly as they continue to find more hosts. One theory that Barry discounted was that physicians simply got better at preventing and treating complications of the infection such as pneumonia. Preventive measures taken by the authorities to limit public contact in theatres and eateries,too,may have helped. Spitting and smoking in public were also prohibited in some places.

Whats the swine flu connection?

According to a recent study published by the New England Journal of Medicine,the swine flu or the H1N1 virus is an offshoot of the 1918 scourge. Influenza viruses,notes the study,have eight genes,two of which code for virus surface proteins hemagglutinin H and neuraminidase N,which allow the virus to enter a host cell and spread. There are 16 H subtypes and nine N subtypes,making 144 HN combinations. Since 1918,the virus has drawn on a bag of evolutionary tricks to survive in one form or another and to spawn a host of novel progeny viruses with novel gene constellations,through the periodic importation or exportation of viral genes,the study says.