An epidemic occurs when an infectious disease spreads rapidly to many people. For example, in 2003, the severe acute respiratory syndrome (SARS) epidemic took the lives of nearly 800 people worldwide. disease outbreak happens when a disease occurs in greater numbers than expected in a community or region or during a season. An outbreak may occur in one community or even extend to several countries. It can last from days to years. Sometimes a single case of a contagious disease is considered an outbreak.
Quick Answer. Bitumen is primarily used to pave roads. It is a brown or black mixture of hydrocarbons, which is derived from petroleum. The consistency of bitumen varies from viscous to solid, and in its solid form, it is commonly known as asphalt. Continue Reading.
Bitumen is also frequently called tar or pitchâthough, properly speaking, tar is a byproduct of the carbonization of coal and pitch is actually obtained from the distillation of coal tar. Bitumen is defined by the U.S. Geological Survey as an extra-heavy oil with an API gravity less than 10Â° and a viscosity greater than 10,000 centipoise.