What Is a Viral Infection?

Types and Treatment of Common Viruses

Man sick in bed
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We hear about "viral infections" a lot. Chances are good that you have been diagnosed with one at some point in your life. But the term can be used to describe a lot of different illnesses. A viral infection is any type of infection that is caused by a virus.

What is a Virus?

A virus is a germ that is smaller than a bacteria. Viruses are encapsulated by a protective coating so they are more difficult to kill than bacteria.

They are harder to treat because they are not susceptible to antibiotics like bacteria are because of their protective coating. However, viruses cannot grow or exist without host cells - they must be in a living organism (such as the human body) to survive.

Common Viral Infections

Viral infections can cause illnesses as minor as the common cold and as severe as AIDS. Many times people will be diagnosed with a viral infection but not get any more specific information about the virus that is causing the symptoms. Usually when this happens, the symptoms are relatively minor and you will recover without any treatment. Health care providers don't always know the exact virus that is causing the illness. This is when you will get the diagnosis of a "viral infection" with no specific name.

Common Viral Infections Include:

  • The Common Cold - The most common viral infection is the common cold, which can be caused by many different viruses. Most often, the cold is caused by an adenovirus, coronavirus or rhinovirus. Symptoms are typically mild and last between a week and 10 days.
  • Influenza - This is the virus that causes the seasonal flu. There are hundreds of strains of influenza that can cause flu symptoms, and the virus mutates from year to year. Although the flu isn't serious for everyone, hundreds of thousands of people in the US are hospitalized every year. Worldwide, it is estimated that between 250,000 and half a million people die from the flu each year.
  • Bronchitis  - Often caused by a bacteria, virus, or even chemicals,the most common form of Bronchitis is the viral version. It can cause a cough that lasts for weeks and is a common complication of both the common cold and the flu.
  • Gastroenteritis - Known as the stomach flu, Gastroenteritis is a very common viral infection. This unpleasant illness causes symptoms, such as vomiting and diarrhea, and is highly contagious. Gastroenteritis may be caused by viruses, such as rotavirus and norovirus, among others
  • Croup - A virus that occurs almost exclusively in children under the age of 8, Croup can be very scary for both the child who gets it and their parents. Croup is characterized by a cough that sounds like a seal barking. Some children may also experience stridor, which is a whistling sound made when the child is inhaling.

Treating Viral Infections

Antibiotics do not kill viruses and using them to treat viral infections just leads to antibiotic resistance. There are only a few antiviral medications available to treat very specific viruses, and they are not always effective.

However, there are vaccines available to help prevent many infections. If you have a minor illness and your health care provider tells you that it is a viral infection, follow your health care provider's advice.

Most likely he will recommend that you take it easy, treat the symptoms you have with appropriate over the counter medicines, and wait for your symptoms to resolve. Remember to rest as much as possible, stay hydrated, and contact your health care provider if your symptoms worsen or change significantly. 


"Viral Infections." Medlineplus 23 July 08. National Institute of Allergy and Infectious Diseases. 08 Aug 08.

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