Outbreaks have occurred around the world since at least the 14th century.

No one knows for certain why so few serious outbreaks have occurred.

Only one outbreak occurred, during a 56-day trip across the open sea.

When outbreaks do occur, it is usually in the summer or early fall.

More than 7 Outbreaks occur - a loss for the players.

This outbreak is also occurring among members of the same population in Israel.

An outbreak may occur in one community or even extend to several countries.

But for many other agents natural outbreaks might never occur.

When the outbreak occurred, the members of this family were among the first captured.

Indeed, if an outbreak occurs, the only sure way to fight it is to go inside and shut your door.