New York officials are trying to calm city residents after the announcement that a staff member of CBS News has tested positive for anthrax.

City officials say they do not yet know how the employee came into contact with skin anthrax. But an NBC News staff member was infected with the same form of the bacteria by handling mail.

A seven month-old baby who visited the ABC network has also been diagnosed with anthrax.

New York City Health Commissioner Neal Cohen is asking people not to rush to overcrowded emergency rooms unless they have been at the scene of an event that is under investigation. "It does to make sense to have people who are essentially well walk into our emergency rooms, to crowd the emergency rooms whereby people who need to be triaged and seen, who indeed are sick are going to kept waiting longer," he said.

Officials say all of those diagnosed are responding well to antibiotic treatment.