Order Now
Menu
  Back to all posts Health Essays

What is a virus? Why are they so difficult to control?

by Expert writer-Eloquence | 31 Mar 2017

Viruses are microscopic particles of 20-300nm in size, obligate intracellular parasites; they can reproduce only by invading and taking over other cells as they lack the cellular machinery for self reproduction. Host range includes a wide variety of animal and plants. There are viruses which can infect bacteria and they are called batceriophage. A complete virus particle is called virion consisting of its simple nucleic acid (either RNA or DNA) and a protein coat called capsid. Viruses with DNA as genetic material are called DNA virus ( eg: herpes virus or Adenovirus etc) and those with RNA as genetic material are called RNA viruses ( e.g.: Foot and Mouth disease virus, SARS virus, HIV etc). Virus encoded proteins form the capsid. The nucleic acid and the capsid together termed as nucleocapsid. Certain viruses have a membrane or envelope covering the nucleoacpsid and they are called enveloped viruses. The envelope is usually of glycolipid and the lipid membrane itself and any carbohydrates present are entirely host-coded (The Influenza virus and HIV use this strategy to evade the immune system).

Need essay sample on

"What is a virus? Why are they so difficult to control?" topic?

We will write a custom essay sample specifically for you

Proceed

Since viruses use the machinery of a host cell to reproduce and reside within the host cell, they are difficult to eliminate without killing the host cell. Viruses used different mechanisms to evade the immune system of the host cell. The most commonly used strategies include antigenic variation, antigenic shift and drift. Influenza virus uses both antigenic shift and antigenic drift to evade the immune system. Antigenic variation can occur through three broadly defined genetic processes: gene mutation, recombination, and switching results in pathogens that are immunologically distinct from the parental strains there by escaping the immune system of the host .Antigenic shift involves between two different subtypes of the same virus coinfect a single cell and exchange RNA segments to form a new subtype. Antigenic drift is by changing the surface protein mainly haemagglutinin and Neuraminidase proteins in case of influenza virus. Mutations in the RNA or DNA causes change in the surface protein and host immune system fails to identify the viral proteins and this will facilitate the viral persistence in the host cell and making it difficult to control.

Reference:

Fileds Virology, David M.Knipe, Peter M Howley, Diane E Griffin, Robert A Lamb, Malcom A Martin, Bernard Roizman, Stephan E Stratus, Source: Lippincott Williams & Wilkins (LWW), 5th edn, 2007.

Learn more:
Substance Abuse What is the role of non-governmental organizations in assuring the health of the public Means Available for U.S Citizens to Obtain Health Care Coverage

Do You need a paper on this topic?

Order Your Essay
Writer avatar

Professor Harvey

№15 In global rating

169

finished papers

133

customer reviews

98%

success rate

Writer avatar

Prof_Nyamags

№17 In global rating

115

finished papers

90

customer reviews

98%

success rate

Writer avatar

Expert Joy

№9 In global rating

122

finished papers

102

customer reviews

100%

success rate

Writer avatar

Dr. Lydia Writer

№18 In global rating

529

finished papers

334

customer reviews

97%

success rate

Writer avatar

MandyTheWriter

№2 In global rating

602

finished papers

404

customer reviews

100%

success rate

Writer avatar

Dr.webb

№14 In global rating

327

finished papers

228

customer reviews

96%

success rate

Writer avatar

Prof. Winny

№4 In global rating

86

finished papers

64

customer reviews

100%

success rate

Writer avatar

Dr Martha

№7 In global rating

563

finished papers

416

customer reviews

95%

success rate

Writer avatar

Writer Banice

№10 In global rating

425

finished papers

316

customer reviews

98%

success rate

Writer avatar

leahjoe

№11 In global rating

770

finished papers

549

customer reviews

96%

success rate

Order your paper now!

I need
My email
By clicking “Continue”, you agree to our terms of service and privacy policy. We’ll occasionally send you promo and account related emails.

EssayLab Reviews

  • Jason (student)

    I asked Essay Lab to write an essay for me and received paper the next day after I ordered it! Thank you!

  • Kimberly (student)

    Awesome WORK! If I ever need to write my essay – I will use only EssayLab!

  • Matt (student)

    These people are lifesavers! Just ask – “write me an essay” and they will start right away!

Support contacts

[email protected]