viral infection


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viral infection

any of the diseases caused by one of approximately 200 viruses pathogenic to humans. Some are the most communicable and dangerous diseases known; some cause mild and transient conditions that pass virtually unnoticed. If cells are damaged by the viral attack, disease exists. The signs of the infection reflect the anatomical location of the damaged cells. Viruses are introduced into the body through nonintact skin or mucous membranes or through a transfusion into the bloodstream or transplantation, by droplet infection through the respiratory tract, or by ingestion through the digestive tract into the GI system. The pathogenicity of the particular virus depends on the rapidity of replication, the enzymes released, the part of the body infected, and the particular action of the virus. After it enters the body, the virus attaches to and enters a cell. The virus directs the cell to produce new virions, using chemical building blocks and energy available in the parasitized cell. The virus has now taken over the cell. After a variable period of time, masses of fully grown viruses appear, each able to survive outside the cell until more susceptible cells are found. In poliovirus infection, one parasitized cell may produce more than 100,000 poliovirus particles in a few hours. Techniques used in viral identification and immunization are based on the essential fact that viruses can multiply only inside living cells. Inoculation of susceptible animals, tissue culture media, and chick embryos allows cultivation of viruses for study and identification and for the preparation of vaccine. Other techniques can also be used in the diagnosis of the cause of viral infection, including serological tests, fluorescent antibody microscopic examination, microscopic examination, and skin tests. In many viral diseases, including mumps, smallpox, and measles, one attack confers permanent immunity. In others, immunity is short-lived. The incubation period for viral infection is usually short, the viruses do not circulate in the bloodstream, antibodies do not form, and most often immunity does not develop. Exposure to a few viruses results in immunity to that virus and to other closely related viruses. Some vectors are able to spread several viruses, but only one at a time. Mechanisms of natural resistance to viral infection are poorly understood, but susceptibility to a particular virus is somehow species-specific; for example, chickenpox, caused by the varicella zoster virus, is seen only in humans. A protective substance, interferon, is elaborated naturally in small amounts in the body. It is cell-specific and species-specific but not virus-specific. Interferon may act as a broad spectrum antiviral agent, protecting the body from the effects of many viral infections, stopping the synthesis of viral nucleic acid within the parasitized cell. See also specific viral infections. Also called viral disease.

viral infection,

n an infection by a pathogenic virus. A virus acts on the cell nucleus, taking over the genetic material within the nucleus and replicating itself.

Patient discussion about viral infection

Q. What are the causes of viral blisters on the skin? For a few months now I've been having these hard viral blisters on my fingers. The only way to get rid of them is with freezed carbon. It does go away with that treatment- after a few weeks but then a new one appears. How can I prevent it from "attacking" again??

A. These viral blisters you are describing are caused by HPV (papilloma virus), and are very hard to get rid of without treatment with freezed carbon. Many of us have the virus but not everyone gets the actual infection. There is not a proved way of preventing from it to happen again after treatment, unfortunately..

More discussions about viral infection
References in periodicals archive ?
The boss said: "Rodney has a viral infection and is getting tests done in Holland so we hope to know more on Tuesday.
The test correctly identified viral infection and avoided false negatives in 89% of the patients with viral infection (sensitivity).
This randomised control trial aimed to assess the role of EPs[R]7630 in asthma attack frequency after upper respiratory tract viral infection.
Dallas: August 23 -- (BNA) The United States of America has detected more than 60% of the "West Nile" viral infections within the past seven days as federal officials described it as a massive epidemic.
ISLAMABAD -- People can protect them against viral infections, especially during autumn and winter, with vitamin D supplementation, researchers found during a study.
Previous studies had suggested viral infection might cause exacerbation of IPF in a majority of patients who have the condition, which occurs most often in people between 50 and 70 years of age.
New DNA viruses identified in patients with acute viral infection syndrome.
The fact that HMPV was not recovered in the last BAL sample does not rule out such viral infection since paramyxoviruses are very labile (1), and the culture may not have been incubated long enough for a cytopathic effect to be observed.
And on the basis of other reports of bacterial mortality rates from viral infection, they conclude that such infections may account for a surprising 30 to 60 percent of bacterial mortality in ocean environs.
Researchers are detecting drug-impervious viral infections in some AIDS patients, a trend that makes treatment extremely difficult and suggests that viruses common in the general population may be outwitting the few drugs scientists have developed to combat them.
NEW YORK -- Christopher Kennedy Lawford today announced his new role in helping to educate America about hepatitis C, a silent viral infection of the liver that affects an estimated four million Americans - 70 percent of whom are unaware of their disease.
Virus-associated hemophagocytic syndrome is a fulminant disorder associated with systemic viral infection and characterized pathologically by multiple-organ infiltration of hemophagocytic histiocytes into the lymphoreticular tissues.