Tissue fragments were formalin fixed, paraffin embedded and hematoxylin-eosin stained. For lung sections, Grocott, Brown-Hopps and Ziehl-Neelsen stainings were performed for the identification of fungi, bacteria and acid-fast bacilli, respectively. Lung fragments were sent for microbiological investigation using rRT-PCR to the Instituto Adolfo Lutz in Sao Paulo. Seasonal influenza A and swine influenza A detection was performed using the CDC protocol [10] . The RT-PCR test used for bacteria identified DNA from Haemophilus influenzae and Streptococcus pneumoniae.