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5-O Agency : Together We Share, We Learn

~ Virus : Be Alert & Be Prepared!

Posted by faisalrenzo on April 7, 2011


Definition of Virus

A microorganism smaller than a bacteria, which cannot grow or reproduce apart from a living cell. A virus invades living cells and uses their chemical machinery to keep itself alive and to replicate itself. It may reproduce with fidelity or with errors (mutations)-this ability to mutate is responsible for the ability of some viruses to change slightly in each infected person, making treatment more difficult.

Viruses cause many common human infections, and are also responsible for a bevy of rare diseases. Examples of viral illnesses range from the common cold, which is usually caused by one of the rhinoviruses, to acquired immunodeficiency syndrome (AIDS), which is caused by the human immunodeficiency virus (HIV).

Viruses may contain either DNA or RNA as their genetic material. Herpes simplex virus and the hepatitis- B virus are DNA viruses. RNA viruses have an enzyme called reverse transcriptase that permits the usual sequence of DNA-to-RNA to be reversed so the virus can make a DNA version of itself. RNA viruses include HIV and the hepatitis C virus.

What Is The Adenovirus?

A group of viruses responsible for a spectrum of respiratory disease as well as infection of the stomach and intestine (gastroenteritis), eyes (conjunctivitis), and bladder (cystitis) and rash. Adenovirus respiratory diseases include a form of the common cold, pneumonia, croup, and bronchitis. Patients with compromised immune systems are especially susceptible to severe complications of adenovirus infection. Acute respiratory disease (ARD), a disorder first recognized among military recruits during World War II, can be caused by adenovirus infections under conditions of crowding and stress.

Adenoviruses are transmitted by direct contact, fecal-oral transmission, and occasionally waterborne transmission. Some types of adenoviruses are capable of establishing persistent asymptomatic infections in the tonsils, adenoids, and intestines. Shedding of the virus can occur for months or years after the initial infection.

Some types of adenoviruses are endemic (constantly present) in some parts of the world, and infection is usually acquired during childhood. Other types of adenoviruses cause sporadic infection and occasional outbreaks. For example, epidemic keratoconjunctivitis (eye infection) is associated with certain adenoviruses (serotypes 8, 19, and 37). Epidemics of fever with conjunctivitis are associated with waterborne transmission of some adenovirus types, often centering around inadequately chlorinated swimming pools and small lakes. ARD is most often associated with adenovirus types 4 and 7 in the US. Enteric adenoviruses 40 and 41 cause gastroenteritis, usually in children.

The clinical spectrum of disease associated with certain adenoviruses depends on the site of infection. For example, infection with adenovirus 7 acquired by inhalation is associated with severe lower respiratory tract disease, whereas oral transmission of the virus typically causes no or mild disease.

Outbreaks of adenovirus-associated respiratory disease have been more common in the late winter, spring, and early summer. However, adenovirus infections can occur throughout the year.

Adenovirus infection is diagnosed in the laboratory by antigen detection, polymerase chain reaction (PCR), virus isolation, and serology. Since adenovirus can be excreted for prolonged periods, the presence of virus does not necessarily mean it is associated with disease.

There are no effective medications to treat adenovirus infection. Adenovirus infections typically do not cause permanent problems or death. The exceptions are infection in an immunodeficient patient and ARD which can be fatal.

Vaccines were developed for adenovirus serotypes 4 and 7, but were available only for preventing ARD among military recruits. Beginning in 1971, all (American) military recruits were vaccinated against adenovirus, but the sole manufacturer of the vaccine halted production in 1996. And as supplies dwindled, adenoviral infection reemerged in the US military.

Strict attention to good infection-control practices is effective for stopping nosocomial (hospital-based) outbreaks of adenovirus-associated disease, such as epidemic keratoconjunctivitis. Maintaining adequate levels of chlorination is necessary for preventing swimming pool-associated outbreaks of adenovirus conjunctivitis.

The virus is approximately 70 nanometers in diameter and contains DNA. Over 40 types of adenoviruses have been recognized. Adenoviruses can be genetically modified for use in gene therapy.

What is the Adenovirus and should I be concerned may be your first question. There are many facets to consider when talking about various viruses including contagiousness, seriousness of infection, and how to protect yourself, among others.

Adenovirus structure

How Do Viruses Spread?

Viruses can spread in many different ways. Plants transmit viruses to one another through small insects. The influenza virus (the flu) for example, is spread by the microscopic particles that a person emits when coughing or sneezing. These tiny particles that are ejected into the air can be inhaled by humans and this is one of the most common ways that the flu spreads.

How Do Our Bodies Protect Us From Viruses?

The human body is a marvel of science. Our bodies have natural defenses against foreign invaders such as viruses, that will provoke an immediate immune response when detected. Our natural immune response can be boosted by certain vaccines which will help us to fight off viruses that otherwise would take over our immune system.

So What Is The Adenovirus?

The Adenovirus or Adenoviridae to put the name into scientific terms, are medium sized icosahedral viruses with 53 different serotypes. A serotype is simply a classification for a series of microorganisms. It can help to think of serotypes as the “family” of the virus. These serotypes are responsible for between 5-10% of upper respiratory infections in children as well as various other infections in adults. All vertebrates are susceptible to Adenoviruses and were first discovered in human adenoids, where they derive their name from.

The Adenovirus in humans can cause upper respiratory disease, conjunctivitis, and gastroenteritis. The Adenovirus’ variants are very common in children and can often cause diarrhea. The virus is much more common in children and infants than adults and can often spread quickly through daycare centers and schools.

Interestingly, the majority of us will have experienced at least one adenoviral infection by age 10. Because of the many types of adenoviral infections, a child may be repeatedly infected with different variants of the virus.

Source : http://www.medterms.com/; http://www.adenovirus.com/

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