A quarantine is a restriction on the movement of people, animals and goods which is intended to prevent the spread of disease or pests. It is often used in connection to disease and illness, preventing the movement of those who may have been exposed to a communicable disease, yet do not have a confirmed medical diagnosis. It is distinct from medical isolation, in which those confirmed to be infected with a communicable disease are isolated from the healthy population. Quarantine considerations are often one aspect of border control.
US President Richard Nixon greeting the Apollo 11 astronauts in NASA's mobile quarantine facility
The quarantine ship Rhin, at large in Sheerness. Source: National Maritime Museum of Greenwich, London
Isolating a village in Romania whose inhabitants believe that doctors poison those suspected of cholera (1911)
The quarantine hospital building (lazaretto) at the historic Columbia River Quarantine Station near Knappton, Washington
A pest is any organism harmful to humans or human concerns. The term is particularly used for creatures that damage crops, livestock, and forestry or cause a nuisance to people, especially in their homes. Humans have modified the environment for their own purposes and are intolerant of other creatures occupying the same space when their activities impact adversely on human objectives. Thus, an elephant is unobjectionable in its natural habitat but a pest when it tramples crops.
Carpet beetle larvae damaging a specimen of Sceliphron destillatorius in an entomological collection
Pests, such as these termites, often occur in high densities, making the damage they do even more detrimental.
Feral pigeons can become very numerous in cities.
Caltrop, Tribulus terrestris, is sometimes considered a pest plant because of its sharp spiny burrs, shown here in a person's foot.
