Describe the types of viruses on the type of the host cell and give their economic importance.

• On the basis of the type of host, viruses can be classified into 3 types -
  

1) Animal viruses:- Those viruses which infect animals and causes various diseases. For example, Retrovirus.

2) Plant viruses:- Those viruses which infect plants. For example, Tobacco Mosaic Virus.

3) Bacteriophage:- Those infecting bacteria. For example, Temperate phages

• The virus contains the characteristics of both living and non- living organisms so they can be utilised in the field of biotechnology.
• Bacteriophage is used in water preservation as it destroys the bacteria and keeps the water fresh.
• Bacteriophage helps in the recycling carbon in the marine environment.
• Virotherapy uses viruses as vectors to treat various diseases, used in the treatment of cancer and gene therapy.
• The virus contains various proteins, therefore, it can be used in the production of proteins such as vaccines, antigens and antibiotics.
• Viruses are mainly responsible for the rapid destruction of harmful algal blooms.