Concepts of Virology

Concepts of virology Definition Virology is a branch of characteristics, microbiology that primarily deals with the study ofviralvarious typesandof viruses, including their agents, submicroscopic, parasites, diseases, particles of genetic material contained inimmunity, the proteinability layer. toVirology is ora school ofhost science that mainly focuses on aspects such as its destroy infect cells, itsof evolution, classification, structure, composition, several ways of infecting it, various ways cultivating it, its use in the laboratory. , various methods for isolating them and their physiology. a. Virus Viruses non-cellular microscopic material and proteins that can attackareliving cells. They belong to organisms the viridaecomposed family andofthegenetic virus genus. b. Characteristics of viruses • They do not have a cell nucleus. • They do not have an organized cell structure. • They usually have one or two strands of DNA or RNA. • They are encased in a protective layer of protein called a capsid. • They don't breathe, don't metabolize and don't grow but they reproduce. • They are considered both living and non-living creatures, as they are inactive outside the host cell, and active when inside the host cell. c. Virus type Based on the type of nucleic acid, viruses are classified into the following types: • RNA viruses Viruses thator have RNA as their RNA. geneticSome material are called RNAbyviruses. They caninbehumans singlestranded double-stranded diseases caused RNA viruses includecommon cold of, hepatitis, polio, West Nile fever, influenza, SARS, and measles. All plant viruses are examples RNA viruses.Mutation rates are higher for RNA viruses. Therefore, this can be considered as one of the main reasons for the lack of preventative efforts towards effective vaccines toviruses treatthat anddiffer prevent certain viral diseases.Double-stranded RNAbacteria, viruses consist of different greatly based on their host viruses such as fungi, genomes, virions, organization.Single-stranded RNA is categorized based on sense, namely positive sense and and negative sense. a. Positive sense RNA is similar to mRNA. They are usually translated into host cells. b.RNANegative sense RNA must be converted into positive sense RNA before translation using the polymerase. • DNA viruses Viruses that have genetic material areusually called double-stranded DNA viruses. They DNA and they replicate usingDNA DNAaspolymerase. They are DNAdepend but in on some cases, they canof beDNAsingle-stranded and most viruses are examples viruses.BasedDNA.Bacteriophages, on the type of host andcyanophages, genetic material. Thereanimal are three types of viruses. 1.Animal VirusesThey –Viruses that infect and live in animal cells, including humans, are called animal viruses. contain DNA or RNA as genetic material. Some examples of animal viruses are rabies virus, influenza virus, polio virus, mumps virus, etc. 2.Plant Viruses –Viruses that infect plants are called plant viruses. They contain RNA as genetic material, which remains in ayellow proteinvirus, coating. potato virus, tobacco mosaicencased virus, beet turnipSome yellowexamples virus etc.of plant viruses are 3.Bacteriophage –Viruses that attack and infect bacterial cells are called bacteriophages. They contain DNA as material. There orareonetypes Usually each type of bacteriophage willgenetic only attack one species strainofofbacteriophages. bacteria. d. Viral Diseases There are common many viruses that can infectwhich humans andmain makecause themofsick. One ofinfectious diseases The most virus is influenza is the flu. Other diseases caused by viruses include the common cold, measles, mumps, yellow fever, hepatitis, AIDS, etc. Some viruses also cause certain types of cancer. The most common of these are cervicalcalled canceroncoviruses and liver cancer. e. Clinical Virology and Veterinary Virology Clinical virology is the field of virology concerned withis the study ofof viruses that cause pathology inprevention humans. Veterinary virology, on the other hand, the field virology that deals with the and treatment of animal viruses, viral agents, and other diseases caused by viruses. For example, diseases, arterial viruses, pestiviruses, etc. Veterinary virology is also an important fieldprion in clinical virology.