Tracking the 2009 H1N1 influenza virus in the Italian region Campania.

A novel swine-origin influenza A (H1N1) virus affecting humans was detected in April 2009 in Mexico, Canada, and USA. The S-OIV infection caused a mild to severe febrile respiratory disease throughout the world. Here, we briefly review the main features of influenza A viruses, which caused also other pandemics in the past, and focus in particular on the epidemiology data of the H1N1 influenza in the Italian region Campania, which resulted the most affected by the S-OIV and the one with more lethal cases.