a. pereda , c. perfumo , and d. r. perez contributed to the concept and design of the study ; a. rimondi , m. angel , j. ye , t. sutton , m. dibrbora , v. olivera , and m. i. craig analyzed and interpreted the virological and molecular data ; j. cappuccio , m. quiroga , and m. machuca performed necropsies , analyzed , and interpreted the histopathological data ; a ferrero provided technical support ; a. pereda , c. perfumo , and d. r. perez revised and approved the final version of the manuscript . phylogenetic tree of hemagglutinin 
 ( 1a ) , na ( 1b ) , and mp ( 1c ) genes . unrooted trees were generated by 
 the neighborjoining method in 11 the paup * program . viruses characterized in this study are 
 highlighted in bold , and swine influenza clusters are identified in 
 colored boxes . h1n1pdm corresponds to h1n1 2009 pandemic virus , 
 ch1n1a to classical swine h1n1 , rh1n1b to triple reassortant swine 
 h1n1 , h1n2c to triple reassortant swine h1n2 , huh1d to humanlike 
 swine h1 , hun1 or hun2 to humanlike swine n1 and n2 , 
 respectively , and swn1 to swine n1 .