Swine Flu 2009 attacks lungs more than seasonal flu

The new (pandemic) H1N1 virus replicated well throughout the lower respiratory tract and more extensively than did both seasonal H1N1 virus (which replicated mainly in the bronchi) and HPAI H5N1 virus (which replicated mainly in the alveoli).”

via Ferreting out pandemic H1N1 pathogenicity; Building a better mousetrap and H5N1 virus. – influenza monitor.