American scientists believe that the 1918 Spanish Flu pandemic was so deadly because it triggered a tremendous immune response in the human body which made it destroy its own cells. Spanish Flu was estimated to have killed over 50 million people – young adults were worst hit.

You can read about this new study in the journal Nature.

Researchers infected mice with a reconstructed H1N1 virus. They observed that not only did the mice suffer severe lung disease, but also their immune systems responded ferociously to the infection – the immune response continued for several days after they had died. Most of the mice became seriously ill within 24 hours and died within five days.

Team leader, Dr John Kash, University of Washington, said “What we think is happening is that the host’s inflammatory response is being highly activated by the virus, and that response is making the virus much more damaging to the host. The host’s immune system may be overreacting and killing off too many cells, and that may be a key contributor to what makes this virus more pathogenic.”

The team would like to find out exactly why the immune system responds so aggressively, but fails to destroy the infection. Finding this out might help us find a way of fighting the present H5N1 avian flu virus strain.

The world population in 1918 was about 1.8 billion (US Census Bureau). Today it is about 6.5 billion. In 1918 3.6% of the world’s population died from Spanish flu. 3.6% of today’s global population is 234 million.

Genomic analysis of increased host immune and cell death responses induced by 1918 influenza virus
Nature doi:10.1038/nature05181
John C. Kash, Terrence M. Tumpey, Sean C. Proll, Victoria Carter, Olivia Perwitasari, Matthew J. Thomas, Christopher F. Basler, Peter Palese, Jeffery K. Taubenberger, Adolfo Garc?a-Sastre, David E. Swayne and Michael G. Katze
Click here to see first paragraph in Nature

Written by: Christian Nordqvist
Editor: Medical News Today