Edith is almost right, but the pest (not to be confused with "a pest" is a particular kind of plague, namely bubonic plague.

bubonic plaque: as writeaway has said, in Dutch it is called Builenpest (bubonic plague), De Pest, zwarte dood. It is caused by a bacterium (Yersinia pestis).

Builenpest (bubonic plague ) kenmerkt zich door vergroting van lymfeklieren, dood
treedt in zonder behandeling in 60% van de gevallen, binnen 3 tot 5 dagen ...
www.bwk.tue.nl/fago/colleges/ biolag/3biolag/3mqbiolag.htm


The bacterium is passed from an infected rat to a non-infected rat by being bitten by a flea. The flea bites the infected rat and the germ moves into and lives in the flea's stomach. The flea's stomach becomes filled with the bacterium. The flea can no longer digest blood, when it bites a human, rat or another animal the flea throws up into the bite causing the victim to become infected

A person can get plague by being bitten by an infected flea, by direct contact with the body juices from an infected animal, by inhalation of airborne drops or particles from humans or animals. Within four to six days after exposure the human victim begins to show symptoms.

After the human is infected the bacterium moves through the bloodstream to the lymph nodes. The lymph nodes become enlarged and painful. During this time a fever starts to develop and headache, chills and extreme exhaustion follow. As the untreated bacterium continues to develop in the bloodstream a severe blood infection develops known as septicemic plague. This blood infection causes bleeding under the skin, which will look dark purple or black, the dried blood under the skin causes this. This bleeding and drying of the blood under the skin is how the bubonic plague became known as the Black Death.

http://members.hometown.aol.com/_ht_a/nathan19901162/myhomep...

for more information about the Black Death:

Introduction to Medieval History The Great Famine (1315-1317) and the Black
Death (1346-1351) Dictionary and Thesaurus ... The Black Death of 1347-1351. ...
www.ku.edu/kansas/medieval/108/ lectures/black_death.html

The Black Death, 1348
... The Black Death, 1348. ... I (translated by Richard Aldington illustrated by
Jean de Bosschere) (1930); Gottfried, Robert, The Black Death (1983). ...
www.ibiscom.com/plague.htm