An experiment to reconstruct the deadly 1918 flu virus has given a new insight into how the infection took hold. Scientists discovered a severe immune system reaction was triggered when mice were infected with the recreated virus. The US team believe the extreme immune response could have provoked the body to begin killing its own cells, making the flu even deadlier. The study, published in Nature, may aid the hunt for new treatments. The 1918 pandemic took about 50 million lives. The devastating infection, which is thought to have originated in birds, left young adults worst hit. Scientists in the...