A virus is defined as any of a various number of submicroscopic parasites that can infect any animal, plant or bacteria and often lead to very serious or even deadly diseases. A virus consists of a core of RNA or DNA, generally surrounded by a protein, lipid or glycoprotein coat, or some combination of the three. No virus can replicate without the help of a host cell, and though they can be spread, viruses lack the ability of self-reproduction and are not always considered to be living organisms in the regular sense.Some of the most common or best known viruses include the human immunodeficiency virus (HIV), which is the virus that causes AIDS, the herpes simplex virus, which causes cold sores, smallpox, multiple sclerosis, and the human papilloma virus, now believed to be a leading cause of cervical cancer in adult women. The common human cold is also caused by a virus.Since a great deal of mystery still surrounds the origins of most modern viruses, ways to cure these viruses and the diseases they cause are still in the very early stages of development.
Latest about Viruses, Infections & Disease
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Experts explain why you're more likely to catch a cold in the winter than in warmer seasons of the year.
How does E. coli get into food?
Dangerous strains of E. coli bacteria can infiltrate the food supply through many different routes, experts explain.
'Mystery disease' in Congo turned out to be malaria — and potentially, another disease
An initially "unknown" illness affecting hundreds in the Democratic Republic of the Congo may be attributable to malaria, malnutrition and a viral infection. But investigations are ongoing.
Avian influenza: Bird flu spread triggers state of emergency in California
The declaration of a state of emergency in California over avian influenza comes within days of the first severe human case of bird flu in the U.S.
Fatal familial insomnia: A genetic condition where people never sleep again
As fatal familial insomnia progresses, patients completely stop sleeping and enter a coma-like state that results in death within months.
Person in Louisiana hospitalized with H5N1 in nation's 1st severe case
A person in Louisiana has been hospitalized with the United States' first serious case of H5N1 bird flu, following 60 milder cases this year.
Bat poop used to grow cannabis kills 2 in New York in unusual cases
Two men from Rochester, New York died from a type of pneumonia after being exposed to a harmful fungus living in bat poop used to grow cannabis.
Flesh-eating human parasite sweeping across Central America is raising concerns in US — what to know
New World screwworm was largely eradicated from the U.S. and Central America in the 1960s and 1980s, respectively. But the potentially fatal parasite is starting to make a comeback, U.S. officials say.
