August 14, 2013

What Are Coronaviruses? Learn Key Facts About Them


A Coronavirus was first isolated in 1937 - it was an avian infectious bronchitis virus which had (and still has) the ability to seriously devastate poultry stocks. According to the Health Protection Agency (HPA), UK, it can also infect the urogenital tract of chickens, and eventually spread to various organs in its body. Over the last 70 years, scientists have found that related coronaviruses can infect mice, rats, dogs, cats, turkeys, horses, pigs and cattle.

Following the explosive spread of the new strain of MERS coronavirus from Saudi Arabia, the Middle East and into other parts of the world, it becomes imperative to learn what this virus is and what damage it can do. More importantly, is the need to protect against infection by understanding how it is spread.

According to Medilexicon's medical dictionary, the Coronavirus is "a genus in the family Coronaviridae that is associated with upper respiratory tract infections and possibly gastroenteritis in humans." This article deals with important facts regarding the coronaviruses as a whole and, by extension, the new MERS-CoV virus.

What are coronaviruses?

Coronaviruses are common viruses that most people get some time in their lives. Human coronaviruses usually cause mild to moderate upper-respiratory tract illnesses, like the common cold.

Coronaviruses are named for the crown-like spikes on their surface (see below). "Corona" in Latin means "halo" or "crown". There are four main sub-groupings of coronaviruses, known as alpha, beta, gamma, and delta.

MERS-CoV virus particles (as seen by electron microscopy)

Human coronaviruses were first identified in the mid-1960s. The six coronaviruses that can infect people are: alpha coronaviruses 229E and NL63, and beta coronaviruses OC43, HKU1, SARS-CoV (the coronavirus that causes severe acute respiratory syndrome, or SARS), and MERS-CoV (the coronavirus that causes Middle East Respiratory Syndrome, or MERS).

There are many coronaviruses that naturally infect animals. Most of these usually infect only one animal species or, at most, a small number of closely related species, but not people. However, SARS-CoV can infect people and animals, including monkeys, Himalayan palm civets, raccoon dogs, cats, dogs, and rodents. MERS-CoV has also been found to infect people and animals, including camels.

How common are human coronavirus infections?

People around the world commonly get infected with human coronaviruses 229E, NL63, OC43, and HKU1. Approximatley 30% of common colds are caused by two human coronaviruses - OC43 and 229E. Two exceptions are SARS-CoV and MERS-CoV.

SARS-CoV was first recognized in China in November 2002. It caused a worldwide outbreak with 8,098 probable cases including 774 deaths from 2002 to 2003. Since 2004, there have not been any known cases of SARS-CoV infection reported anywhere in the world.

MERS-CoV was first reported in Saudi Arabia in 2012. It has since caused illness in people from dozens of other countries. All cases to date have been linked to countries in and near the Arabian Peninsula. CDC continues to closely monitor the MERS situation globally and work with partners to better understand the risks of this virus, including the source, how it spreads, and how infections might be prevented. More about MERS-CoV.

Who can get infected?

Most people will get infected with one or more of the common human coronaviruses in their lifetime. Young children are most likely to get infected. However, people can have multiple infections in their lifetime.

How do I get infected?

The ways that common human coronaviruses spread have not been studied very much. However, it is likely that human coronaviruses spread from an infected person to others through the air by coughing and sneezing, and by close personal contact, such as touching or shaking hands.

These viruses may also spread by touching contaminated objects or surfaces then touching your mouth, nose, or eyes.

When can I get infected?

In the United States, people usually get infected with common human coronaviruses in the fall and winter. However, you can get infected at any time of the year.

What are the symptoms?

Common human coronaviruses usually cause mild to moderate upper-respiratory tract illnesses, like the common cold, that last for a short amount of time. Symptoms may include runny nose, cough, sore throat, and fever. These viruses can sometimes cause lower-respiratory tract illnesses, such as pneumonia. This is more common in people with cardiopulmonary disease or compromised immune systems, or the elderly.

MERS-CoV and SARS-CoV can cause severe illness. To learn more about MERS Symptoms and Complications, click here.

How can I protect myself?

There are currently no vaccines available to protect you against human coronavirus infection. You may be able to reduce your risk of infection by doing the following:
  • wash your hands often with soap and water
  • avoid touching your eyes, nose, or mouth with unwashed hands
  • avoid close contact with people who are sick
For information about hand washing, see CDC’s Clean Hands Save Lives!

What should I do if I get sick?

If you have cold-like symptoms, you can help protect others by doing the following:
  • stay home while you are sick
  • avoid close contact with others
  • cover your mouth and nose with a tissue when you cough or sneeze, then throw the tissue in the trash and wash your hands
  • clean and disinflect objects and surfaces

How do I get diagnosed?

Your healthcare provider can order laboratory tests on your blood or nose/throat swabs to confirm whether your illness is caused by a common human coronavirus. However, these tests are not used very often because people usually have mild illness. Also, testing may be limited to a few specialized laboratories because human coronaviruses cannot be cultivated in the laboratory easily, unlike the rhinovirus, another cause of the common cold.

Are there treatments?

There are no specific treatments for illnesses caused by human coronaviruses.

Most people with common human coronavirus illness will recover on their own. However, you can do some things to relieve your symptoms:
  • take pain and fever medications (Caution: Aspirin should not be given to children)
  • use a room humidifier or take a hot shower to help ease a sore throat and cough
If you are sick, you should:
  • drink plenty of liquids
  • stay home and rest
If you are concerned about your symptoms, you should see your healthcare provider.

1). Centers for Disease Control: About Coronavirus. Accessed 12 August 2013. Available here:
2). Medical News Today: What Are Coronaviruses? What Do Coronaviruses Cause?. Published: 19 Feb 2013. Accessed 2 August 2013. Available here:

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