Diphtheria (Greek διφθέρα (diphthera) "pair of leather scrolls") is an upper respiratory tract illness caused by Corynebacterium diphtheriae, a facultative anaerobic, Gram-positive bacterium. It is characterized by sore throat, low fever, and an adherent membrane (a pseudomembrane) on the tonsils, pharynx, and/or nasal cavity. A milder form of diphtheria can be restricted to the skin. Less common consequences include myocarditis (about 20% of cases) and peripheral neuropathy (about 10% of cases).

Diphtheria is a contagious disease spread by direct physical contact or breathing the aerosolized secretions of infected individuals. Historically quite common, diphtheria has largely been eradicated in industrialized nations through widespread vaccination. In the United States, for example, there were 52 reported cases of diphtheria between 1980 and 2000; between 2000 and 2007, there were only three cases as the diphtheria–pertussis–tetanus (DPT) vaccine is recommended for all school-age children. Boosters of the vaccine are recommended for adults, since the benefits of the vaccine decrease with age without constant re-exposure; they are particularly recommended for those traveling to areas where the disease has not been eradicated.

Sean Justin Penn (born August 17, 1960) is an American actor, screenwriter and film director, also known for his left-wing political and social activism (including humanitarian work). He is a two-time Academy Award winner for his roles in Mystic River (2003) and Milk (2008), as well as the recipient of a Golden Globe Award for the former and a Screen Actors Guild Award for the latter.

Penn began his acting career in television with a brief appearance in a 1974 episode of Little House on the Prairie, directed by his father Leo Penn. Following his film debut in 1981's Taps and a diverse range of film roles in the 1980s, Penn emerged as a prominent leading actor with the 1995 drama film Dead Man Walking, for which he earned his first Academy Award nomination and the Best Actor Award at the Berlin Film Festival. Penn received another two Oscar nominations for Sweet and Lowdown (1999) and I Am Sam (2001), before winning his first Academy Award for Best Actor in 2003 for Mystic River and a second one in 2008 for Milk. He has also won a Best Actor Award of the Cannes Film Festival for She's So Lovely (1997), and two Best Actor Awards at the Venice Film Festival for Hurlyburly (1998) and 21 Grams (2003).