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Virus

A virus is a microscopic particle that can infect the cells of a biological organism. Viruses can only replicate themselves by infecting a host cell and therefore cannot reproduce on their own. At the most basic level, viruses consist of genetic material contained within a protective protein coat called a capsid; the existence of both genetic material and protein distinguishes them from other virus-like particles such as prions and viroids. They infect a wide variety of organisms: both eukaryotes (animals, fungi and plants) and prokaryotes (bacteria). A virus that infects bacteria is known as a bacteriophage, often shortened to phage. The study of viruses is known as virology, and those who study viruses are known as virologists.

It has been argued extensively whether viruses are living organisms. Most virologists consider them non-living, as they do not meet all the criteria of the generally accepted definition of life. They are similar to obligate intracellular parasites as they lack the means for self-reproduction outside a host cell, but unlike parasites, viruses are generally not considered to be true living organisms. A primary reason is that viruses do not possess a cell membrane or metabolise on their own - characteristics of all living organisms. Examples of common human diseases caused by viruses include the common cold, the flu, chickenpox and cold sores. Serious diseases such as Ebola, AIDS, bird flu and SARS are all also caused by viruses.

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Health & Medicine News

August 27, 2025

Researchers propose that the U.S. could safely drop adult tetanus and diphtheria boosters, saving $1 billion annually, since childhood vaccinations provide decades of protection. Evidence from the ...
Scientists at Kyoto University have uncovered a hidden protein complex that organizes DNA in sperm stem cells, a discovery that reveals surprising ties between fertility and cancer. When this protein, called STAG3, is missing, sperm stem cells ...
University of Minnesota researchers developed a 3D-printed scaffold that directs stem cells to grow into functioning nerve cells, successfully restoring movement in rats with severed spinal cords. This promising technique could transform future ...
Scientists have cracked one of chemistry’s toughest challenges with indoles, using copper to unlock a spot once thought too stubborn to change. The discovery could pave the way for easier, cheaper ...
Knee osteoarthritis is a major cause of pain and disability, but routine X-rays often do more harm than good. New research shows that being shown an X-ray can increase anxiety, make people fear exercise, and lead them to believe surgery is the only ...
A nationwide study found that recent colds caused by rhinoviruses can give short-term protection against COVID-19. Children benefit most, as their immune systems react strongly with antiviral defenses, helping explain their lower rates of severe ...
Australian teachers are in crisis, with 9 in 10 experiencing severe stress and nearly 70% saying their workload is unmanageable. A major UNSW Sydney study found teachers suffer depression, anxiety, and stress at rates three to four times higher than ...
Painkillers we often trust — ibuprofen and acetaminophen — may be quietly accelerating one of the world’s greatest health crises: antibiotic resistance. Researchers discovered that these drugs not only fuel bacterial resistance on their own ...
Researchers uncovered that the Maui wildfires caused a spike in deaths far higher than reported, with hidden fatalities linked to fire, smoke, and lack of medical access. They warn that prevention rooted in Native Hawaiian ecological knowledge is ...
Living near the ocean may actually help you live longer. A new nationwide study found that people in coastal regions enjoy life expectancies a year or more above the U.S. average, while city dwellers near inland rivers and lakes may face shorter ...
A large study of nearly 16,000 adults found no link between eating animal protein and higher death risk. Surprisingly, higher animal protein intake was associated with lower cancer mortality, supporting its role in a balanced, health-promoting ...
Scientists have identified compounds that block bitter taste receptors activated by saccharin and acesulfame K. The most promising is (R)-(-)-carvone, which reduces bitterness without the cooling side effect of menthol, potentially making sugar-free ...

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