Pathological Changes Associated with the 2009 H1N1 Virus

Abstract

Between April 23, 2009, and May 15, 2009, we performed 15 autopsies on deceased patients in whom probable influenza had been diagnosed either clinically or macroscopically. Small samples of lung tissue were obtained and taken for analysis to the Institute of Epidemiological Diagnosis and Reference in Mexico City. Five infections with the 2009 pandemic influenza A (H1N1) virus were confirmed with the use of a real-time reverse-transcriptase–polymerase-chain-reaction assay, after it was determined that these patients were seronegative for influenza B virus, respiratory syncytial virus, parainfluenza virus (types 1, 2, and 3), and adenovirus.¹ From these five patients, organ samples were collected, fixed in 10% formalin, embedded in paraffin, and stained with hematoxylin and eosin. In the remaining 10 patients in whom the 2009 H1N1 virus was not detected, histopathological analyses identified bacterial pneumonia.