Why measles is the most contagious of all viruses

SAN FRANCISCO (KGO) -- Measles is the most contagious of viruses. Here's an explanation as to why.

A prominent Mayo Clinic researcher says when the measles virus gets into the lungs it hijacks a cell to get into the immune system, replicates, and then uses the trachea as a trampoline.

A single cough or sneeze hurtles the virus through the air in enormous quantities.

Measles can linger on a surface, such as a doorknob, for two hours.

If one person has measles, then 90 percent of the people nearby who are not immune will also become infected. That explains why it's spreading so rapidly.

Ninety-two percent of doctors now attribute the outbreak to parents not vaccinating their kids.

For full coverage on the measles outbreak, click here.