Author details– Abhishek Kumar, 4th year integrated MSc,NISER
Simpal Kumar Suman,4th year B.Tech Biotechnology,RPCAU
Do you think that war can be only between different countries? The answer is no. There is an ongoing war between the virus and human beings. Viruses pose an existential threat to the human beings.
A virus is classified as neither living nor non-living. It is intermediate between living and non-living entity and acts as an intracellular parasite. Viruses have a simple structure in which a stretch of the DNA or RNA sequence is encapsulated in a protein coat. Viruses are host-specific in nature. They can be classified on the basis of nucleic acid configuration into single or double-stranded DNA and single or double-stranded RNA. When the virus is not infecting a cell, it exists as non-living viral particles. Viral particles are simply a packet of macromolecules and cannot reproduce on their own. These viral particles can infect cells and hack into the central dogma of the host to force the cell’s genetic machinery to replicate and translate viral genes. Viruses do not have their own metabolism; thus, utilize the host machinery to replicate. The replication rate of viruses is extremely fast that results in a lot of mutations during their replication. These mutations help them in gaining resistant against drugs. Even the most effective drugs are rendered useless after a few years. This is not a small matter and it should not be taken lightly, because viral epidemic can even cause the extinction of human beings. There have been numerous viral outbreaks in recent years. If you visit the World Health Organization (WHO) site, you will see that most of the disease outbreaks are viral outbreaks. Viruses are invaders of the host body (e.g., human) and viral infection can lead to death or weakening of the host. So viruses can be termed as indifferent terrorists, which do not need to discriminate while infecting the hosts. They neither require political agenda nor resources and still can kill thousands of human beings without a moment’s notice.
The bigger question for now is in this 21st century, how can we counter dangerous viruses which pose a threat to the existence of the human race. The answer is Biotechnology. The modern biotechnological tools and techniques can be used in drug design and development against viruses but the simple structure, small genome size, rapid mutations, host dependence, genomic variability in nucleic acid configurations makes the process of drug designing difficult. These reasons are also responsible for the failure of drugs and increase both the time and cost of new drug testing, research and development. The treatment of viral diseases is not an easy task for doctors or researchers. It has many challenges. Viruses not only affect the humans. Viruses have a broad spectrum host infection ability. At inter-kingdom levels, organisms are fighting against viruses. From bacteria to higher organisms (plants and animals), viruses are effective in all kingdoms and can even infect other viruses.
List of some viruses having ability to infect humans:
Impact on Human
|Swine Flu virus||H1N1, SIV||Fever, lethargy, difficult breathing;||infected pigs||No specific treatment, just general antivirals are given|
|Bird flu virus||H5N1, H7N9(Human infection)||Severe pneumonia and eye infections;||Infected fowl||Neuraminidase inhibitors|
|AIDS||HIV||Weakening of immune system;||Sexually transmitted||Highly active antiretroviral therapy (HAART) slows progression but does not cure|
|Human Papiloma Infection||HPV18 and HPV 16||Warts and precancerous lesions;||Sexually transmitted||No specific treatment|
|Herpes||HSV-1 and HSV-2||Red blisters, fever and cold sores in mouth;||Contacting surface skin of infected person||No specific treatment, just general antivirals are given|
|Zika fever||ZIKV||Fever, red eyes, joint pain, headache and maculopapular rashes;||Carrier mosquitoes||No specific treatment, just general antivirals are given|
|Ebola hemorrhagic fever||Ebola virus||Fever, sore throat, muscular pain, headaches, diarrhea and bleeding;||Direct contact||No specific treatment, just general anti -virals are given|
|Nipah virus||Henipa virus||Acute respiratory infection, headache, myalgia, vomiting and sore throat;||infected fruits or direct contact||No specific treatment, just general anti virals are given|
|Measles||Rubeola virus||Cough, Runny nose, gray spots and conjunctivitis;||Physical contact or exposure to infected fluids||No specific treatment, keep yourself hydrated|
|Dengue Virus||DENV||Fever, headache, joint pain and rash;||Carrier mosquitoes||No specific treatment, just general anti virals are given|
|Chikungunya||CHIKV||Fever, joint pain, head ache and rashes;||Carrier mosquitoes||No specific treatment, just general anti virals are given|
|Hepatitis B||HBV||Vomiting, yellowish skin, dark urine and abdominal pain;||Exposure to infectious body fluids||Antiviral therapy slows progression but does not cure|
|Rabies||Lyssavirus||Inflammation of brain;||Infected animals||Human rabies immunoglobin and rabies vaccine|
In the above table, you can see that we don’t have a cure for most of the viral diseases. Most effective way to combat viral diseases is to take vaccines to prevent infection. A vaccine contains a weakened or dead pathogen and helps in attaining acquired immunity for diseases. So, how are we fighting against viral epidemics or outbreaks against which the vaccines are not available? In any viral epidemic like the recent Nipah virus epidemic first, the infected people and the people coming in contact with them are isolated. They are administered with a cocktail of antivirals, all of which target different aspects of the life cycle of a virus (against which the virus has not attained resistance). These slow down the rate of viral proliferation. In the same time, the patients are given immune supplements which helps the body to fight against the disease. An early identification and a quick action during an epidemic are essential; however, the current strategies are simply stopgap measures, not a permanent solution. If there is an epidemic of a virus which our immune system even with immune supplements is unable to counter, it can result in the extinction of human species. Viruses can also be used as biological weapons, so, any research in virology should be done under strict regulations.
It’s not like the humans are not fighting back. There has been a gradual increase in the research for the production of antivirals in last 50 years. The governments have increased large-scale vaccination and the epidemics are being handled more cautiously and decisively. Some viral infections like smallpox and polio (in India) has been eradicated (no known new cases for 1-3 years). Different biotechnological strategies against viral infection have been developed. Small interfering RNAs packaged in lipid nanoparticles can interfere with viral mRNA encoding for nuclear coat proteins. Antisense polymers are synthesized which can prevent protein production by specifically binding to the mRNA. Interferons are used to boost immune response during infection. Antibodies extracted from infected organisms that develop immunity against the virus can be used during epidemics. Many new drugs have been obtained by screening of natural products from traditional medicinal plants. Molecular computer modelling is nowadays used for drug discovery by analyzing natural compounds and using that information design new compounds with better inhibitory power. A combination of drugs which can work in synergy with each other are used in combination with other existing therapies in a severe case.For example, the first effective drug for Ebola disease is ZmappTm which is the result of a collaboration between Mapp Biopharmaceutical, Inc. and LeafBio (San Diego, CA), Defyrus Inc. (Toronto, Canada), the U.S. government and the Public Health Agency of Canada (PHAC). ZmappTmbelongs to a new class of drug called Plantibody.It is an experimental new drug that is being developed to treat patients with Ebola.ZMapp™ is a cocktail of three “humanized” monoclonal antibodies synthesized in transgenic plants, specifically tobacco. The trials of this drug against Ebola virus was effective.Clinical trials are still going on for proper approval by FDA (Food and Drug Administration) for satisfaction to all parameters before marketing. Research and Development in Biotechnology is going to play an important role in the fight against viruses in the coming era. Every month new techniques and strategies like this are being discovered but only a few are even reaching the level of clinical trials; however, there is always a fear of a new epidemic. It seems as if humans are losing the war against the virus. It is high time the world recognized the threat of viruses, and the countries need to invest more resources in the research of antivirals.A
Abhishek Kumar, 4th year integrated MSc,
School of Biological Sciences,
National Institute of Science Education and Research Bhubaneswar(NISER),Odisha
Simpal Kumar Suman,4th year B.Tech Biotechnology
Faculty of Basic Sciences and Humanities,
Dr.Rajendra Prasad Central Agricultural University (RPCAU),Pusa, Bihar
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