The technique used to create the first synthetic polio virus, revealed last week, could be also used to recreate Ebola or the 1918 flu strain that killed up to 40 million people.

What is even more worrying is that there are easier ways of recreating microbes. You can simply add key genes to a close relative. The key in all cases is knowing the genetic sequence. That raises fundamental questions about the wisdom of publishing the genomes of deadly pathogens on the internet.