
Vaccine production:-
Vaccines provide immunity against viral diseases . the conventional vaccines synthesised using live attenuated viruses(weakened in force or effect ) or killed viruses are aay to produce and economic.
Gene Therapy:-
we all know that a gene is a region of DNA that encodes a functional RNA or protein product. A defective gene produces a defective /non functional protein product and causes disease. Gene therapy is the introduction of functional gene. Into human cells to correct defective genes by replacing them . gene therapy is largely used in cancer treatment e.g bone marrow transplant in blood cancer.
Cancer Therapy:
Some viruses taht causes cancer are called oncoviruses. viruses can be directly used to prevent cancer by being the source of anticancer vaccines e.g vaccine against hepatitis B virus (Causes hepatic cancer ) and human papillomavirus ( cervical cancer) are commercially available.
Bacteriophage Therapy:-
You have already studied that bacteriophage are bacteria eating viruses. Therefore bacteriophage can be used for destruction of bacterial pathogens . this therapy has been used for destruction of bacterial pathogens. This therapy has been used to successfully treat Staphylococcal and E. coli infections and appears to be very promising.
Role of virus In Research

Viruses have been extensively used for research ad they infect all three domains of life ( bacteria , archae and eukaryota ( Viruses have the unique ability to insert genetic content into host cells , therefore are commonly used as vector in recombinant DNA technology and research procedure. Bacteriophage are the routinely used viral vectors in genetic engineering. The lambda and M13 phage are the most commonly used E. coli phages.
Virus based diagnosis
Viruses have a major role in diagnostic techniques like southern blotting , cloning , DNA and RNA sequencing of disease etc. Which are commonly employed in diagnosis. Viruses are used as vectors in these techniques.
Viral biopesticides :-
They are much less significant than bacterial pesticides . Research and development on various viruses as potential bio control agents is still going on. Baculoviruses are the most most important group of viruses used as bio pesticides.