Viruses are mostly known for their aggressive and infectious nature. But not all viruses are bad. Dr. Marilyn Roossinck, professor of plant pathology and environmental microbiology at Pennsylvania State University, University Park, said that “Viruses, like bacteria, can be important beneficial microbes in human health and agriculture,”. Her review on beneficial viruses appeared in print on April 24 in the Journal of Virology, published by the American Society for Microbiology.
Scientists are continuously understanding host-virus interaction and viral physiology so that they may be able not only to control harmful viruses but also to use some of the viruses to control plants and animal pathogens and environmental protection. There are three fields in which the benefits of viruses can be studied.
1- Beneficial viruses in Health
It is true that most viral relationships with their hosts are pathogenic, which means that they cause diseases ranging from a mild cold to serious conditions such as SARS, and they work by invading the host cell, controlling cellular mechanisms and releasing new viral particles that continue to infect more cells and caused illness. But some viruses can kill harmful germs while others can fight more dangerous viruses, such as “probiotics” (a type of microorganism that increases the immune response of humans), and we also have many protective viruses in the body.
Viruses in medicine
Viruses are used as vectors or carriers that carry the material required for the treatment of a disease to various target cells. They have been extensively studied in the treatment of inherited diseases and genetic engineering, as well as cancers.
Viruses in bacteriophage therapy
These are highly specific viruses that can attack, infect, and (if selected correctly) destroy pathogenic bacteria. Bacteriophages are believed to be the most numerous type of viruses representing the majority of viruses present on Earth. These are basic tools in molecular biology.
Viruses and vaccines
Viruses have been used since Edward Jenner’s time in vaccines. Jenner used cowpox viruses to inoculate people against smallpox infection.
Vaccines against polio, measles, chickenpox, etc. they use live, weakened viruses that cause disease or dead viral particles. These, when introduced into a healthy individual, help the immune system to recognize and build immunity to the virus. The body remembers the organism and attacks it in the event of a subsequent infection, thus avoiding disease.
Virus-directed enzyme prodrugs Therapy (VDEPT)
Viruses in cancer prevention and control
Different viruses like Hepatitis B virus (HBV), hepatitis C virus (HCV), Epstein-Barr virus (EBV) and human papillomavirus (HPV) contribute to about 10-15 % global burden of human cancers. Conventional chemotherapy or molecular target therapies have been used to treat virus-associated cancers. Effective immunization or vaccination campaigns for the prevention of these viral infections have led to a remarkable reduction in the cancers caused by these infections. Different Antiviral therapies have yielded promising results in cancer prevention and treatment.
- Antiviral treatments against chronic HBV and HCV infections have achieved a significant reduction in the incidence of hepatocellular carcinoma in treated patients.
- Therapeutic HPV vaccine and RNA-interference-based therapies for treating HPV-associated cervical cancers also showed some encouraging results.
2- Beneficial viruses in agriculture
Genetic engineering and modification methods can be used to make modified genomes that can be transported to plants and animals by viruses that act as vectors or vehicles. This method can lead to more productive transgenic animals and plants. Scientists have successfully induced different genes like herbicide tolerance, high nitrogen fixation, high lysine (in corn), increased resistance to pests and diseases, in plants by using a virus as a gene carrier and vector.
In an experiment, it was found that all virus-infected plants were much more drought tolerant.
In Yellowstone National Park, soil temperatures can get quite high in geothermal areas, but some plants can grow very well in these locations with soil temperatures of 115 ° F.
After a few years, other researchers discovered that the plant was colonized by a fungus. Without the fungus, the plant could not tolerate heat. After that, it was discovered that there was a virus in the fungus. So, heat tolerance characteristic in plants was induced by viral induction in plants.
Drought-stressed rice plants after six days without water. The plant on the right is infected with the Brome mosaic virus; the one on the left is “healthy” (that is, virus-free).
Viruses use in biological pest control
- Viruses can also be used to control harmful pests. Traditionally, this has been used in agriculture, but there are also applications in the control of agents important to human health.
- The types of agents used for this purpose may take advantage of the target species, maybe parasites of the target pests, be pathogenic or cause disease in the target species, or maybe competing species.
- Viruses used for pest control are common pathogens that cause diseases of the target species. Although they represent a small amount of total pesticide use, viruses are used for the control of multiple species of insects and also for rabbits.
- Biological agents can produce long-lasting effects and, in some cases, can spread among the target population. They have also been recognized as inherently less toxic than conventional pesticides by the US Environmental Protection Agency. USA
- Its disadvantages include a limited range of action, slow effects compared to chemical agents, high initial treatment costs, low environmental stability, particularly in sunlight.
3- Role of viruses in the environment
- Levels of air pollutants and warming gases over some cities and regions can be significant drops as the viral epidemic spreads like in the case of coronavirus 2020. Researchers in New York told the BBC that due to coronavirus pandemic in 2020 carbon monoxide emission mainly from cars had been reduced by nearly 50% compared with last year.
- Various genetically modified bacterias are prepared with the help of virus vectors to control air pollution, oil spills in water bodies, clean up mercury pollution and detect arsenic in drinking water.
- Transgenic crops produced by virus carriers have remarkably reduced the use of pesticides, herbicides, and fertilizers thus reducing soil and water pollution.
Besides the above three major fields, viruses are also helpful in some minor fields such as…..
Viruses in biological studies
Viruses have been widely used in studies of molecular and cellular biology. These viruses provide the advantage of being simple systems that can be used to manipulate and investigate the functions of cells.
- Viruses have been widely used in genetic research and understanding of genes and DNA replication, transcription, RNA formation, translation, protein formation, and the basic concepts of immunology.
- These have been used in understanding the field of gene therapy. The key element of gene therapy is the introduction of functional genes into the cells of a human patient by a virus vector. This new gene shows the desired functions and corrects the faulty or non-operative genes within those cells.
Viruses in nanotechnology
Nanotechnology deals with microscopic particles. These have various uses in biology and medicine, and nanotechnology has been used in genetic engineering. Viruses can be used as carriers of genetically modified genome sequences to host cells.
Viruses in arms and biological warfare
Viruses may be small, but they have the capacity to cause death and devastation to large populations in epidemics and pandemics. This has led to concerns that the viruses could be used for biological warfare.