Virology is the scientific study of viruses and virus-like agents, focusing on their structure, classification, evolution, methods of infection, and interaction with host organisms. It encompasses research into the diseases caused by viruses, their transmission, diagnosis, prevention, and treatment. As a subfield of microbiology, virology deals with a wide range of viruses, including those that affect humans, animals, plants, and even bacteria (bacteriophages).
Key areas of virology include:
Virus Structure and Classification: Understanding the molecular composition and organization of viruses, such as DNA or RNA viruses, enveloped or non-enveloped, and their shapes (icosahedral, helical, etc.).
Viral Replication: Studying how viruses reproduce by hijacking the cellular machinery of host cells, leading to the production of new viral particles.
Pathogenesis: Exploring how viruses cause diseases, affect the immune system, and interact with host cells.
Epidemiology: Tracking how viruses spread within populations and the factors that contribute to outbreaks and pandemics.
Vaccine and Antiviral Development: Developing preventive and therapeutic measures, including vaccines, antiviral drugs, and immune therapies to combat viral infections.
Virology has gained significant attention due to its role in understanding viruses such as HIV, influenza, coronaviruses (like SARS-CoV-2), and many others that affect global health.
Viruses that infect bacteria are known as phages or bacteriophages. Twort (19l5) described a degenerative alteration in staphylococcal colonies isolated from calf lymph that was transmissible serially via application of culture filtrates from the original growth. d’Herelle (1917) observed that the filtrates of dysentery patient faeces cultures produced transmissible lysis of a dysentery bacillus broth … Read more
What are Poxviruses? Classification of Poxviruses Based on whether they infect insect or vertebrate hosts, the family Poxviridae has been divided into two subfamilies: Chordopoxvirinae and Entomopoxvirinae. The subfamily Chordopoxvirinae encompasses viruses that infect vertebrate hosts and consists of eight genera, at least four of which cause human illness. These are the categories: The genera … Read more
Viral replication is the process of forming of biological viruses in the course of the infection process within the host cells.
A virus has to go through the process of reproduction to generate new, infectious virions which are able to infect cells within the body and subsequent hosts.
Pathogenesis refers to the process by which infection by viruses causes illness. Thus, it is a description of the mechanism by which initial infection triggers the development of disease.
Viral entry is the first phase of infection in the viral life cycle when the virus is in contact with the cell of its host and injects virus-related material into the cell.
The local spread of the infection within the epithelium happens when the virus is released and infects adjacent cells. The infections are typically controlled by the physical limitations of the tissue, and are managed by the inherent immune and innate defenses.
Viruses are extremely immunegenic and cause two kinds of immune responses: the humoral and the cellular.
The range of specificities of B and T cells is derived from changes in the somatic genome and rearrangements.
T B cells and T typically recognise the exact epitopes within the exact virus. B cells recognize the free proteins unaltered in their original 3-D configuration while T cells typically view Ag in a denatured form. Ag in a denatured state together in conjunction with MHC molecules.
The features of an immune reaction for the exact virus can be different for different individuals based on their genetic makeup.
It is responsible for preventing infection by this virus (neutralization).
The IgG and IgM class are particularly relevant. IgM as well as the IgG class are especially important to protect against viral infections, which are often accompanied by viraemia. The antibodies from IgA class are particularly relevant for defense against viraemia. IgA class are essential for infections contracted through the mucosa. (the nose and the intestinal tract)
However, the immune system kills the infected cells that express viruses’ proteins onto their surface including glycoproteins that envelope viruses have and occasionally the essential proteins of these viruses.
A typical vaccine has an ingredient that resembles the microorganism that causes illness and is typically made from weak or dead forms from the microbes, their toxicants, as well as one or more of the surface proteins.
Scientists use a variety of methods for making vaccines. They are based on research on the diseases (caused by bacteria or viruses) the vaccine is designed to be able to prevent, like the way that germs infect cells, and the way the immune system responds to it.
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