Keywords: Influenza virus.png from en Image Influenza virus png Influenza Virus photo from http //www ncbi nlm nih gov/ICTVdb/Images/Murphy/Downloadable 20Graphics 20Files htm A/Hong Kong/1/68 Influenza virus A/Hong Kong/1/68 the causative agent of the 1968 global epidemic Negatively stained virions showing surface projections which contain the receptors by which the virus attaches to host respiratory tract epithelial cells Magnification approximately x70 000 Micrograph from F A Murphy School of Veterinary Medicine University of California Davis PD-USGov Influenzavirus |