A virus is a biological agent that reproduces inside the cells of living
hosts. When infected, a host cell is forced to produce many thousands of
identical copies of the original virus, at an extraordinary rate. Unlike
most living things, viruses do not have cells that divide; new viruses
are assembled in the infected host cell. Over 2,000 species of viruses
have been discovered. A virus consists of two or three parts: genes,
made from either DNA or RNA, long molecules that carry the genetic
information; a protein coat that protects the genes; and in some, an
envelope of fat that surrounds and protects them when they are not
contained within a host cell. Viruses vary in shape from the simple
helical and icosahedral to more complex structures. They spread in many
different ways. Whereas viruses such as influenza are spread through the
air by people when they cough or sneeze, others such as norovirus, which
are transmitted by the faecal-oral route, contaminate hands, food and
water. Rotavirus is often spread by direct contact with infected
children. The human immunodeficiency virus, HIV, is one of several major
viruses that are transmitted during sex. Viral infections often cause
disease in humans and animals; however, they are usually eliminated by
the immune system, conferring lifetime immunity to the host for that
Read more: <https://en.wikipedia.org/wiki/Introduction_to_viruses>
Today's selected anniversaries:
The islands of Saint Pierre and Miquelon (modern city of Saint-
Pierre pictured) were discovered by Portuguese explorer João Álvares
Fagundes near Canada, who named them "Islands of the 11,000 Virgins".
Florence Nightingale and a staff of 38 nurses were sent to
Turkey to help treat wounded British soldiers fighting in the Crimean
The first of the Medicine Lodge Treaties was signed between the
United States and several Native American tribes in the Great Plains,
requiring them to relocate to areas in present-day western Oklahoma.
Korean War: British and Australian troops of the 27th British
Commonwealth Brigade engaged in heavy fighting with North Korean forces
in the Battle of Yongju.
Sri Lankan Civil War: Indian Army soldiers, belonging to the
Indian Peace Keeping Force, entered the Jaffna Teaching Hospital in
Jaffna, Sri Lanka, and began killing about 68–70 patients, nurses,
doctors and other staff members.
Wiktionary's word of the day:
1. (archaic) To jest, ridicule, or mock; to make sport of.
2. (informal) To discharge a thin stream of liquid through the teeth or
from under the tongue.
Wikiquote quote of the day:
To love for the sake of being loved is human, but to love for the sake
of loving is angelic.
--Alphonse de Lamartine
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