Uses of Viruses

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Viruses cause us much harm, however, their infectiouos ability have made them the prime candidate as vectors in gene therapy. Removing the harmful codes in their genome and using them to infect the target host cell and integrate the desired gene into the host genome is the idea.

They do run the risk of infecting the host despite removing the known disease causing part of the viral      genome. Click here to learn more about them.

Another use for viruses would be when they are dead and used as vaccines. This method has been in use for some time now. Click here to more about them.

(Image: www.accessexcellence.org/.../making_vaccines.php)



Apart from being used in the medical sector, viruses have also been introduced as biological pest controls. Read on to learn how they help to control insects which harm crops.

Video of Virus Entry

Video

This video shows the general viewer a simple overview of how a virus infects a host cell and replicates.

Virus Control

The virus is not controlled by antibodies that come in tablets. We can control viral infections of the body only with our immune system. Our white blood cells would combat with these foreign bodies when they are exposed to them. This concept is the basis of vaccines where dead viruses are injected into the body for the immune system to build up defence to it. Eventually, when the virus does infect the patient, he is able to counter the attack.

Viruses mutate at high rate, which impedes the body's immune system to control it. Different strains of a virus are increasingly found today. The flu virus itself has shown many faces, like H1N1 and H5N1.

Scientists have made breakthroughs in controlling virus growth. As mentioned about viruses having viral enzymes to fascilitate their replication and assembly, using enzyme inhibition could stop the virus. Since each step in the life cycle of a virus involves an enzyme, creating drugs that inhibit the enzyme prevents the growth of the virus. The challenges lie in early detection of the infection and the mutation rate of the virus. Using this concept, drugs have been made for the HIV.



Groups of Antiretroviral Drugs


There are five groups of antiretroviral drugs. Each of these groups attacks HIV in a different way.



1. Nucleoside/Nucleotide Reverse Transcriptase Inhibitors NRTIs  --  NRTIs interfere with the action of an HIV protein called reverse transcriptase, which the virus needs to make new copies of itself.

2. Non-Nucleoside Reverse Transcriptase Inhibitors NNRTIs --  NNRTIs also stop HIV from replicating within cells by inhibiting the reverse transcriptase protein.

3. Protease Inhibitors PIs --  which is another protein involved in the HIV replication process.

4. Fusion or Entry Inhibitors --  prevent HIV from binding to or entering human immune cells.

5. Integrase Inhibitors -- interfere with the integrase enzyme, which HIV needs to insert its genetic material into human cells.

(Drugs information from: http://www.avert.org/treatment.htm)

Viruses

Viruses are very small parasites. They infect host cells and cause diseases. However, the detection of viral infection could be difficult as they could remain dormant for long periods before any symptoms are visible. Viruses are acellular, they do not respire outside host cells.

(Image of virus: www.armageddononline.org/.../viruses.html )

Properties

Viral Genome :  DNA or RNA contained in Protein coat or Capsid

Shape            :  Various shapes

Size               :  10 - 100 nm

May or may not have lipid bilayer envelope and contains viral enzymes. These carry out viral replication and assemply.

( Image of various virus shapes: cesarharada.com/pearls/category/structure/ )