What causes virus in humans?

Answer 1

Viruses are spread among the human population the same way bacterial infections are. Many viruses (but not all) are spread by infected people coughing and /or sneezing . If you come into contact with the nasal droplets or mucous the virus can be passed from one host to another. Viruses can be passed on by touching or shaking hands with another person who has the virus .If an infected person touches an item such as a food , a door knob or tap etc and you touch it too a virus can be transmitted to you.This is why washing hands is so important. Sneezing or coughing into your elbow or into a cloth you then dispose of rather than into you hands reduces transmission .

Viruses that cause diarrhoea can be deadly . It is possible to contaminate food with viruses if you fail to wash your hands adequately after toileting . Dirty hands make it possible for harmful viruses (or bacteria ) from the intestine to spread.

Body fluids, such as blood, saliva and semen, can contain viruses. The transmission of such fluids by injection or sexual contact and even kissing pass on viruses like AIDS ,Herpes or Hepatitus.

Viruses are microscopic and can't be seen by the naked eye. They can bee seen by electron Microscopes .They can't multiply on their own and they need to invade living organisms to make more virus particles. Human beings are the perfect social animal to spread Viruses and as we travel widely a virus can be spead across the world in a matter of days (sometimes hours). However not all viruses can be spread by humans or make human beings ill. Some virus are harmless or only infect other species.

Some virus particles can lay dormant for years trapped by ice or in soil. If accidentally ingested or inhaled the Virus can become active again even after thousands of years.

Viruses consist of genetic materials (DNA or RNA) . They are surrounded by a protective coat of protein. They have a special mechanism which makes them capable of latching onto cells and getting inside them where they then begin to duplicate.The cell becomes a virus making factory.

The cells of the mucous membranes in the lungs or nose are particularly vulnerable to virus attacks because they are not covered by protective skin. Entry by an open wound is also possible.