Identifying a Pathogen
In his awesome book on pathogens that jump species, Spillover , David Quammen has one section on how the process of identifying a pathogen proceeds. He uses the SARS breakout of 2003 as an example. When it went global starting at Hong Kong, he writes nobody knew what caused it, hence the name: “Ebola is a virus. Hendra is a virus. Nipah is a virus. SARS is a syndrome.” Most tests in medical labs are designed in a particular way: “Such tests essentially give you a positive, negative, or approximated answer in response to a specific question: Is it this ? Finding an entirely new pathogen is more difficult. You can’t detect a microbe by its molecular signature until you know roughly what that signature is.” So when trying to identify a new pathogen, scientists try growing it in a culture and then peer at it through a microscope. Then they tried peering through an electron microscope, and thus realized it was a coronavirus, i.e., viral particles “encircled by a corona of k...