Diphtheria is a bacterial infection that affects mostly the nose and throat. The groups most at risk are children under the age of 5 and adults over the age of 60. The people most at risk are those who live in crowded or dirty conditions, aren’t well nourished, and those who are not immunized. It is very rare in the United States and Europe since most children are immunized against it. It is more common in those countries where children are not immunized in general practice.

"Diphtheria." www.kidshealth.org. May 2005. Nemours Foundation. 15 Feb. 2008 <http://www.kidshealth.org/parent/infections/bacterial_viral/diphtheria.html>.