Headquarters in new york, this is nbc nightly news with brian williams. Good evening. A disease once thought to be gone in the United States is making a come back and today, the centers for Disease Control pushed back at parents who are declining vaccines for their children. The number of children with measles in this country is spiking, along with mumps and whooping cough and in light of the new numbers, an Infectious Disease expert blamed rumors and conspiracy theories for a fall off in vaccinations. Young parents today havent seen these diseases, and they dont respect or fear them. This is an issue of Public Health and where we begin tonight with dr. Nancy snyderman. Reporter new mom Meredith Greenstein had a scar lately saying three month old raleigh might have been exposed to measles. We knew something had to be done. So on the advice of our pediatrici pediatrician, we took her immediately to the emergency room. Reporter greenstein, an nbc employee, says everything turned out okay