To test a 2009 pandemic influenza A (H1N1) virus strain on selected surfaces, a clinical isolate designated influenza A/Cambridge/AHO4/2009 (AH04) was passaged once in MDCK cells and then grown in Caco-2 cells (colorectal adenocarcinoma cells, ATCC HTB-37 TM ). The virus is a recent isolate from an Received sterile in packaging from manufacturer.