In just one outbreak, 64 people caught measles in eight different regions across Slovenia, Italy and Belgium in less than eight weeks. The outbreak started at an international dog show in Vrtjoba/Šempete, western Slovenia at the beginning of November 2014. Thirty-six people were initially infected (primary cases), who went on to infect nine others (secondary cases), who in turn infected 16 more (tertiary cases).
Measles is more infectious than you think.
Source data from Eurosurveillance (http://bit.ly/1Nl68eS & http://bit.ly/15DDlkD), iss.it and nijz.si.