What is human metapneumovirus, the infectious respiratory disease spiking this year?

John V. Williams is a professor of pediatrics, microbiology and molecular genetics at the University of Pittsburgh.

In the year 2000, Dutch scientists went on a mission of exploration – not to discover lands or riches, but to identify unknown causes of acute respiratory infections.

These illnesses, from the common cold to pneumonia, have been a plague on mankind throughout history. Most are caused by viruses, so if you've ever been told "you probably have a virus" by a clinician, they were likely correct. However, respiratory illnesses can be much more severe than simple colds.