Watch: The tricks that make measles so infectious

Few things set public health departments scrambling like a measles outbreak. The virus is a bear to deal with, even in highly vaccinated populations. That’s because the virus is exquisitely adept at finding people who are susceptible to it, and infecting them.

Its powers are almost legendary. Can a single person infect others in a sports stadium? Yes. An infected person on a plane? Ditto. A doctor’s office? Disneyland? Yessiree.

A combination of factors makes this virus a veritable infecting machine. Its mode of transmission and the period