The process by which influenza virus particles bud from an infected cell is not very well understood. Accumulation of M1 at the inner leaflet of the plasma membrane is thought to be the trigger for the initiation of bud formation. This bud formation continues until the inner core of the virus is completely enveloped. Completion of the budding process requires the membrane at the base of the bud to fuse. Although M1 is thought to be the driving force for bud formation, other viral and cellular proteins have been demonstrated to affect size and shape of the virus particle. Generally, influenza virus particles are either spherical or filamentous and this characteristic morphology is genetically linked to the M segment (Bourmakina, 2003; Roberts, 1998). Host factors such as polarization and the actin cytoskeleton play a critical role in determining the shape of filamentous particles (Roberts, 1998; Simpson-Holley, 2002).