Introduction

Virology is the study of viruses submicroscopic, parasitic particles of genetic material contained in a protein coat and virus-like agents. It focuses on the following aspects of viruses: their structure, classification and evolution, their ways to infect and exploit host cells for reproduction, their interaction with host organism physiology and immunity, the diseases they cause, the techniques to isolate and culture them, and their use in research and therapy. Virology is a subfield of microbiology.

A major branch of virology is virus classification. Viruses can be classified according to the host cell they infect: animal viruses, plant viruses, fungal viruses, and bacteriophages (viruses infecting bacteria, which include the most complex viruses). Another classification uses the geometrical shape of their capsid (often a helix or an icosahedron) or the virus's structure (e.g. presence or absence of a lipid envelope). Viruses range in size from about 30 nm to about 450 nm, which means that most of them cannot be seen with light microscopes. The shape and structure of viruses has been studied by electron microscopy, NMR spectroscopy, and X-ray crystallography.

Classification of viruses

Following the announcement of the initial operational definition of a virus as a filterable agent, attempts were made to identify the properties of viruses that separated them from other microorganisms. To this end, the single defining feature of all viruses is that they are obligate intracellular molecular parasites.

A second inviolate property of viruses is that they do not reproduce by binary fission, which is a method of asexual reproduction where pre-existing cells split into two identical daughter cells. For viruses, the process of reproduction is akin to an assembly line, in which different parts come together to create new viral particles.

In general, viruses contain only one type of nucleic acid (either DNA or RNA) that carries the information necessary for viral replication. Nevertheless, it is clear now that some viruses contain other nucleic acid molecules; for example, in retroviruses, cellular transfer RNAs are essential for the action of the enzyme reverse transcriptase.

The chemical composition of viruses varies between different virus families. For the simplest of viruses, the virion is composed of viral structural proteins and nucleic acid; however, the situation becomes more complex with when dealing with enveloped viruses. The latter types of viruses mature by budding through different cellular membranes that are modified by the insertion of viral proteins.

Study of viruses

Even from the earliest times, it was clear that the filterable agents could not be cultivated on artificial media. Even today, virus isolation in cell culture is still considered the gold standard against which other assays must be compared.

Still, the most obvious method of virus detection and identification is direct visualization of the agent. The morphology of most viruses is sufficiently characteristic to identify the image as a virus and to assign an unknown virus to the appropriate family. Furthermore, certain non-cultivable viruses can be detectable by electron microscopy.

The journal of “Medical Microbiology & Diagnosis” is a peer reviewed medical journal that includes a wide range of topics in this fields including Bacteriology, Clinical and Medical Diagnostics, Parasitology, Bacterial Infections and creates a platform for the authors to make their contribution towards the journal. The editorial office promises a thorough peer review of the submitted manuscripts to ensure quality.

Best Regards,

Mary Wilson,

Associate Managing Editor,

Medical Microbiology & Diagnosis

E-mail: microbiology@jpeerreview.com