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What is a coronavirus?

Coronaviruses are large families of viruses, found in animals. Coronaviruses are zoonotic, meaning they can transmit from animals to humans.

Coronavirus symptoms

Common coronaviruses usually cause mild to moderate respiratory tract illnesses, like the common cold (which itself is a coronavirus). People will come into contact with a common coronavirus at some point in their lives. Coronavirus symptoms can include runny nose, sore throat, headache, fever, cough and general feelings of being unwell.

Common coronaviruses can cause lower-respiratory tract illnesses, such as pneumonia or bronchitis, too. This is more common in people with weakened immune systems, infants and older adults.

Known coronaviruses

Middle East respiratory syndrome, commonly referred to as the MERS virus, was first reported in Saudi Arabia in September 2012. Most MERS patients developed severe respiratory illness with symptoms of fever, cough and shortness of breath. The Centers for Disease Control (CDC) estimated about three or four out of every 10 patients reported with MERS died.

Severe acute respiratory syndrome, or SARS, is a coronavirus first reported in southern China in February 2003. Symptoms ranged from diarrhea, fatigue and shortness of breath, to respiratory distress and kidney failure. The illness spread to more than two dozen countries, in North and South America, Europe and Asia before its containment.

On December 31, 2019, the World Health Organization (WHO) China office learned cases of pneumonia with an unknown cause had been detected in Wuhan City, China. Dubbed COVID-19, it is a novel coronavirus, meaning it is a new strain not previously identified in humans. Patients with confirmed cases of COVID-19 have reported illnesses ranging from mild symptoms to severe illness and death.

The symptoms for COVID-19 have included fever, cough and shortness of breath.

How does a coronavirus spread?

Because coronaviruses are zoonotic, they can spread from animal to human and from human to human. It is believed MERS was originally transmitted from dromedary camels to humans in Saudi Arabia in 2012. Similarly, investigations found SARS was transmitted from civet cats to humans in China in 2002.

Current understanding of COVID-19 is largely based on what we know about similar coronaviruses. COVID-19 is spreading from person to person in China. Spread is limited in countries outside China, including the United States.

COVID-19 is spreading person-to-person:

  • Between people who are in close contact with one another (within about 6 feet).
  • Via respiratory droplets produced when an infected person coughs or sneezes
    • These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs.

Currently it is believed patients are at their most contagious when they are most symptomatic. Some spread might be possible before people show symptoms.

Who is at risk?

People of all ages can be infected by a coronavirus, including COVID-19. Older people, and people with pre-existing medical conditions (such as asthma, diabetes, heart disease) appear to be more vulnerable to becoming severely ill with the virus.

Coronavirus treatment and prevention

There is currently no vaccine to prevent COVID-19. The best way to prevent illness is to avoid being exposed to the disease. There are preventative actions to help mitigate the spread of respiratory diseases, including:

  • Avoid close contact with people who are sick.
  • Avoid touching your nose, eyes and mouth.
  • Stay home when you are sick.
  • Cover your cough or sneeze with a tissue, then throw the tissue in a trash receptacle.
  • Clean and disinfect frequently touched objects and surfaces using a regular household disinfectant spray or wipe.
  • Face masks should be used by people who show symptoms of COVID-19 to help prevent the spread of the disease. Face masks have not been a proven protective measure from respiratory diseases.
  • Wash your hands often with soap and warm water for at least 20 seconds, especially after using the bathroom.