“It devastated my whole organism. I’m still having difficulty swallowing and can’t really eat certain things because it’s all scar tissue. It teaches you to enjoy life to the fullest.”

“But the economy is less a machine than a natural ecosystem, less an engine than a complex organism, like a forest or ocean.”

For a cancer patient, catching pneumonia can be deadly and, as there are around 600 different organisms that can cause pneumonia, doctors have to conduct multiple tests to identify the infection.

They are found in many organisms, including bacteria, yeasts, humans, mice, fruit flies and frogs.

"Cities are also highly connected places where trade happens, and organisms may end up on shipments in planes or boats traveling between cities."