The virus that reportedly caused the 1918 Spanish flu pandemic which killed more people than during World War 1, was apparently so deadly because it triggered an uncontrolled immune system response in victims, scientists have reported in the journal NATURE.

About 50 million people died in the 1918 pandemic. By infecting macaque monkeys with a reconstructed version of the virus, an international team of researchers discovered the virus replicated quickly and unleashed an excessive immune system response in the macaque that destroyed their lungs in days.

Scientific analysis is fine, even to retrospectively discover historical causes, but what happens if this gets out of the laboratory? I believe that research involving monkeys jumped the species divide and ultimately caused HIV - Aids!