Viruses And Diseases

Viruses And Diseases
A virus is a tiny infectious agent that can only replicate when inside another organism's cells. Viruses will infect any type of organisms, animals, plants, human beings all included. Some of the common diseases caused by viruses include influenza, cold sores, chicken pox, and the common cold, while more serious and life threatening cases include the more prevalent AIDS, ebola, avian flu, SARS, swine flu to name but a few. The ability of a virus to cause disease is depicted in terms of its virulence.

There are some diseases however which are still under research to determine whether they are caused by viruses or not, a perfect example being the likely connection between neurological diseases like chronic fatigue syndrome and multiple sclerosis and the human herpes virus 6 (HHV6). Still on point, alarming debate is going on whether the borna virus, which was previously suspected to be the causative agent of neurological diseases in horses, could be the culprit behind psychiatric conditions in humans.

Generally, viruses have diverse mechanisms in which they cause a disease in a living organism, which basically depends on the viral species in question. At the cellular level, mechanisms simply include cell lysis i.e. breaking open and ensuing death of the cell. When dealing with multicelluar organisms, effect can only be felt when all cells die in the entire organism. While a virus will typically disrupt the normal functioning of the body to cause diseases, some can still exist fairly harmless in an organism.

A perfect example of this is the herpes simplex virus, known to cause sores. It is able to remain in a dormant state in the human body. While they can eventually cause diseases, there presence can sometimes be beneficial as the mere presence of it can increase the body's immunity against pathogenic infections like Yersinia Pestis. Note however that some viruses are known to cause chronic or life-long infections, in cases where the virus continues to replicate inside the body regardless of the body's defense mechanism.

This is evident in hepatitis B and C virus infections. In such cases, individuals who are chronically infected are known as carriers as they act as stores of infectious viruses. In a society where many people are carriers, the disease will be termed as endemic. Virologists, the people who study viruses and their behaviors, are however always trying to identify the different viruses so that vaccination and treatment against them can be discovered.