Population-based surveillance for 2009 pandemic influenza A (H1N1) virus in Guatemala, 2009.

Background: In April 2009, 2009 pandemic influenza A H1N1 (2009 H1N1) was first identified in Mexico but did not cause widespread transmission in neighboring Guatemala until several weeks later.

Methodology And Principle Findings: Using a population-based surveillance system for hospitalized pneumonia and influenza-like illness ongoing before the 2009 H1N1 pandemic began, we tracked the onset of 2009 H1N1 infection in Guatemala. We identified 239 individuals infected with influenza A (2009 H1N1) between May and December 2009, of whom 76 were hospitalized with pneumonia and 11 died (case fatality proportion: 4.