Virology
Virology involves the study of viruses, their ecology, classification, and structure.[1] Those who choose this field of work are referred to as a virologists.
Virologists
Virologists study, research, and sometimes find vaccinations for viruses. Virologists can have different levels. The levels are 0-4 without a level one. These levels measure the harmfulness of the viruses virologists work with. Level 0 virologists would deal with viruses such as the common cold. Level 3 would contain viruses such as AIDS. Level 4 deals with the most dangerous viruses. These include Marhburg, Ebola, and Hanta. Level 4 viruses require the most protection. The virologists who deal with these types of viruses must wear bio-safety suits. There are only two level 4 facilities inside the U.S. which have the ability to study these types of viruses: the Center for Disease Control and Prevention (CDC) in Atlanta, and The United States Army Medical Research Institute for Infectious Diseases (USAMRIID) in Maryland.
Virologists may work in varied locations. These locations may range from a rain forest in Africa, to a local hospital, and even a level four lab. Virologists may even help develop vaccines while working for pharmaceutical companies.
Despite attempts to understand the growth of virus in cells occupies most of the efforts of the virologists in recent years, viruses are still a major cause of human diseases.[2]
Education
To become a virologist one must go to school for several years. The number of years depends on the field of virology. Virologists must study several different areas of science. These include epidemiology, microbiology, chemistry, molecular biology, and virology.
Wages
The wage of virologists varies greatly. The factors that affect wage include, but may not be limited to: the bio-hazard level, research done, travel required, and employer. The salary can range from around $30,000 to over $100,000 per year. [3]
Methods used in virology
Cultivation of viruses
A wide range of procedures has been developed for cultivating viruses. In the vast majority of cases it is necessary to supply the virus with appropriate cells in which it can replicate. In a few cases it is possible the cultivation of viruses in cell-free systems.[4] In animal viruses, the culture system for growing a virus consists of living cells and the choice stays among three types of culture systems: living animals, organ culture (e.g. pieces of brain) or cell cultures. The later is divided among three types of cell cultures: primary cells, cell lines and permanent cell lines.[5] Before the advent of cell culture, many viruses were propagated in embryonated chicken eggs.[6]
Isolation of viruses
The virus can be isolated from an infected host collecting material excreted by or secreted, and testing blood or tissue to induce the same symptoms identical to a host, or by the induction of some abnormal pathology in a host substitute or in cell culture.[1]
Centrifugation
After the virus has been propagated, it is usually necessary to remove contaminants before the sample be in conditions to be studied in the laboratory. One of the most common methods for this is centrifugation. Centrifugation can be differential or by density gradient.[4]
Electrophoretic techniques
Detection of viruses and virus components
A major issue is the ability to recognize a viral infection in the host. Initially, as the virus were recognized for their infectivity, the early methods focused on this property, more sensitive and informative. More recently, molecular diagnostic techniques have been developed.[6]
Infective assays
An infective assay measures the concentration (known as the titre) of infective virus in a specimen or a preparation.[4] There are Several classes of assays measuring number of infectious units. Among them, the plaque assay, fluorescent-focus assay, infectious center assay, transformation assay and endpoint dilution assay among others.[6]
Virus genetics
Virus genetics involves a number of issues such as genome sequencing, manipulation of viral genomes and the investigation of gene function and expression.[4] The study of the genome involves other important issues such as the study of genetic drift and antigenic drift. An example is the influenza virus, subject both to genetic drift and antigenic drift.[7]
Fields
fields of virology include:
- Epidemiology
- Field Research
- Biological Warfare
- Lab Research
- Public Health
- Education and Research
- Community Health Assessment
History
| Year | |
|---|---|
| 1774 | Farmer Benjamin Jesty vaccinated his family members using cowpox taken from an infected cow's udder to create immunity in his family and wrote about what happened. Edward Jenner studied these and other events and became accredited as the first to intentionally vaccinate to prevent infectious disease. |
| 1885 | Louis Pasteur used the term "virus" to describe the rabies virus which he experimented with. He created the terms "vaccination" and "virus" to honor Edward Jenner. He also created a scientific basis to follow Edward Jenner's approach to vaccination. |
| 1886 | John Buist took a smallpox patient's lymph from their skin lesions. He found "elementary bodies" in this lymph sample. Those elementary bodies were actually particles of the smallpox virus. |
| 1892 | Dmiti Iwanoski became the first person to distinguish the difference between viruses and other infectious agents. |
| 1898 | Martinus Beijerinick developed the concept that the virus is an entity.Also in 1898 Freidrich Loeffler and Paul Frosch proved that viruses could infect both animals and plants. |
| 1900 | Walter Reed discovered that mosquitoes were capable of spreading yellow fever. |
| 1908 | Erwin Popper and Karl Landsteiner became the first people to discover that humans could be infected by viruses. |
| 1911 | Francis Peyton Rous became the first prove that a virus had the ability to cause cancer. |
| 1915 | Frederick Twort found viruses that could infect bacteria. |
| 1917 | Felix d'Herelle created the term bacteriophage to describe viruses that could infect bacteria. |
| 1935 | Wendell Stanley demonstrated that the tobacco mosaic virus could still be infectious even after crystallization. His works became the first step to characterize a viruses molecular structure. |
| 1938 | Max Theiler created a vaccine to prevent yellow fever. |
| 1939 | Emory Ellis and Max Delbruck created the idea of the one step virus growth cycle. |
| 1940 | Helmuth Ruska became the first to take pictures of virus particles using an electron microscope. |
| 1941 | George Hirst became the first to create a rapid method of measuring eukaryotic viruses. |
| 1945 | Salvador Luria and Alfred Hershey proved that bacteriophages had the ability to mutate. |
| 1949 | John Enders, Thomas Weller, and Frederick Robbins used human tissue culture to grow the polio virus in vitro. |
| 1950 | André Lwoff and his colleagues created the term prophage by discovering lysogenic bacteriophages inside Bacillus megaterium using ultra-violet light. |
| 1952 | Renato Dulbecco demonstrated that bacteriophages are similar to animal viruses in the way that they can form plaques. |
| 1957 | Heinz Fraenkel-Conrat and R.C. Williams demonstrated that virus particles form spontaneously when mixtures of purified TMV RNA and a coat protein were incubated together. |
| 1961 | Sydney Brenner, Francois Jacob, and Matthew Meselson demonstrated that virus protein synthesis was directed by bacteriophage T4 using host cell ribosomes. |
| 1963 | Baruch Blumberg found the HBV virus (hepatitis B virus) |
| 1967 | Nark Ptashne isolated and studied the repressor protein. Also in 1967 Theodor Diener discovered viroids. |
| 1970 | Howard Temin and David Baltimore found reverse transcriptase in retroviruses. |
| 1975 | Bernard Moss, Aaron Shatkin, and their colleagues demonstrate that correct processing during translation is affected by messenger RNA containing a nucleotide cap at the 5' end. |
| 1976 | J. Michael Bishop and Phillip Sharp discover gene splicing. |
| 1979 | The virus smallpox was declared to by the World Health Organization to be eradicated. |
| 1981 | Yorio Hinuma and his colleagues found patients with the adult T-cell leukaemia and isolated the human T-cell leukaemia. |
| 1982 | Stanley Prusiner discovered that scrapie was caused by prions. |
| 1983 | Kuc Montaiguer and Robert Gallo announced that they had discovered HIV. |
| 1985 | The USDA gave the first license to market GMOs. |
| 1986 | Roger Beachy, Rob Fraley and their colleagues helped provide a better understanding of plant's virus resistance by demonstrating that tobacco plants had formed the coat protein of tobacco mosaic virus are resistant to the TMV virus. |
| 1994 | Yuan Chang, Patrick Moore, and their colleagues had identified the human herpesvirus 8. |
| 1999 | The number of cases of people who had AIDS or HIV had risen to 33 million. |
Types of Viral Diseases
References
- ↑ 1.0 1.1 Condit, Richard C. (2006). "2 Principles of Virology". In Knipe, David M.; Howley, Peter M.. Fields Virology (5th ed.). New York: Lippincott Williams & Wilkins. p. 25-58. ISBN 978-0-78176060-7.
- ↑ Fields, Bernard N.; Knipe, David M (1991). "1 Introduction". In Fields, Bernard N.; Knipe, David M.; Chanock, Robert M.; Hirsch, Martin S.; Melnick, Joseph L.; Monath, Thomas P.; Roizman, Bernard. Fundamental Virology (2nd ed.). New York: Raven Press. p. 3. ISBN 0-88167-683-7.
- ↑ Virologists Author Unknown, Mainland CCTT, May 17, 2009
- ↑ 4.0 4.1 4.2 4.3 Carter, John; Saunders, Venetia (2007). Virology: Principles and Applications. New Jersey: John Wiley & Sons. p. 11-29. ISBN 978-0-470-02387-7.
- ↑ Dimmock, N. J.; Easton, A. J.; Leppard, K. N. (2007). "2: Some Methods for Studying Animal Viruses". Introduction to Modern Virology (6th ed.). Malden, MA/Garsington Road, Oxford: Blackwell Publishing. p. 18-19. ISBN 1-4051-3645-6.
- ↑ 6.0 6.1 6.2 Flint, S. J.; Enquist, L. W.; Racaniello, V. R.; Skalka, A. M. (2004). "2: Virus Cultivation, Detection, and Genetics". Principles of Virology: Molecular Biology, Pathogenesis, and Control of Animal Viruses (2nd ed.). Washington, D.C.: ASM Press. p. 30-44. ISBN 1-55581-259-7.
- ↑ Webster, Robert (1999). Esteban Domingo; Webster, Robert; Holland, John. ed. Origin and Evolution of Viruses. San Diego: Academic Press. p. 378-379. ISBN 0-12-220360-7.
- ↑ The History of VirologyAuthor Unknown, Academic Press, May 4, 2009
- ↑ Jäger, Joachim; Pata Janice D (2002). "2.1: Viral RNA-Directed Polymerases:Structure and Function Relationships". In Holzenburg, Andreas; Bogner, Elke. Structure-Function Relationships of Human Pathogenic Viruses. New York: Kluwer Academic/Plenum Publishers. p. 68-69. ISBN 0-306-46768-2.
- ↑ Types of Viral diseases Author Unknown, wrongdiagnosis.com, May 21, 2009