A new finding by British researchers reveals that the vaccinia poxvirus spreads virus by bouncing from one cell to the other before it finds an uninfected cell.

As per the lead researcher Geoffrey Smith of Imperial College London, this ‘viral bouncing’ is the reason for experiments in which vaccinia spreads much faster across a dish of cells than viral reproduction rates should allow.

Smith was quoted by Nature as saying, “A virus might hit a cell that's already infected, get bounced away, hit another, get bounced away again ... and eventually it will find a cell that is uninfected, which it can enter... The virus is so smart.”

A cell infected by vaccinia rapidly begins producing two viral proteins, known as A33 and A36. A complex is formed at the cell’s outer membrane with proteins, which marks the cell as infected.

This connection causes the cell to produce a long filament made up of the building-block protein actin – that thrusts the virus outward.

Smith says that this means that vaccinia deceives cells into saying: “Hey guys, we're infected already, no point coming in here. You need to go somewhere else.”