Ask the Doctor
- There are several different types of human coronaviruses, many of which cause upper respiratory illnesses.
- On February 11, 2020, the World Health Organization officially named the disease causing the 2019 novel coronavirus outbreak, identified in Wuhan, China, COVID-19.
- In COVID-19, the “CO” stands for “corona,” “VI” for “virus,” and “D” for disease. Previously the disease was called “2019 novel coronavirus” or “2019-nCoV”.
- A novel coronavirus is considered a new type of coronavirus that had not previously been discovered. COVID-19 is not the same type of mild, cold-causing coronavirus that is passed among humans.
- Other types of coronaviruses include 229E, NL63, OC43, or HKU1, which are not the same as COVID-19. Patients diagnosed with COVID-19 are evaluated and cared for differently than other patients diagnosed with a different coronavirus.
What is a Coronavirus?
There are very many coronaviruses in nature, and they infect a variety of animals, humans, or both. Researchers have detected over 70 coronavirus species in bats alone in China. Researchers first recognized coronaviruses that infect humans in the 1960s.
They generally spread in respiratory secretions between animals, animals to people, or person to person. New coronaviruses may occasionally spread from animals to cause infections in humans. This happened with MERS-CoV (from camels) and SARS-CoV (possibly bats or civet cats).
To date, seven coronaviruses that infect people are known:
- 229E (alpha coronavirus)
- NL63 (alpha coronavirus)
- OC43 (beta coronavirus)
- HKU1 (beta coronavirus)
- MERS-CoV (a beta coronavirus that causes Middle East respiratory syndrome, or MERS)
- SARS-CoV (a beta coronavirus that causes severe acute respiratory syndrome, or SARS)
- 2019 novel coronavirus (2019-nCoV), COVID-19, or Wuhan coronavirus (a beta coronavirus similar to SARS-CoV)
Most human infections occur with the first four coronaviruses listed. They commonly cause “common cold” symptoms and do not cause deaths.
Researchers believe the last three only recently evolved to infect humans and have caused outbreaks associated with deaths. It is possible that they may cause more severe disease because they are new coronaviruses that most human immune systems do not have prior antibodies to and are unaccustomed to.
Most domestic pets such as dogs and cats are not known to spread serious coronavirus infections to humans. However, animals raised for food and sold at live animal markets have spread coronaviruses such as SARS-CoV, MERS-CoV, and probably Wuhan coronavirus (2019-nCoV).
In 2012, researchers first identified MERS-CoV in humans and traced it to markets and livestock farms in Saudi Arabia, where people raise camels for milk and meat. Outbreaks, including spread to other countries, have originated in the Arabian Peninsula. About 3-4 out of 10 infected people have died from it.
In 2002, researchers first identified SARS-CoV in Guangdong Province in southern China. It caused a global outbreak that ended in July 2003.
Researchers suspect an animal source, possibly bats or civet cats, from a live animal food market. Smaller incidents occurred afterward, three being from laboratory accidents.
2019-nCoV appeared in Wuhan, Hubei Province, China, and spread rapidly. Based on early information, it appears to have originated from an animal and seafood market. Investigation is yielding new information daily and is updated at CDC, 2019 Novel Coronavirus.
- Coronaviruses are very common. Most coronaviruses that infect humans cause mild symptoms like a common cold and go away on their own. Very few may cause severe disease such as viral pneumonia that may lead to death.
- Coronaviruses spread easily from person to person by inhalation of respiratory secretions or by contact of respiratory secretions with the eyes, nose, or mouth. Rarely, fecal contamination can transmit COVID-19.
- Frequent cleansing of hands with soap and water or alcohol-based sanitizers and avoiding crowds can help prevent infection with coronavirus, influenza, and many other upper respiratory infections. Experts also recommend that people cough or sneeze into their elbow or cover their mouth and nose with a tissue that they can throw away.
- Coronaviruses also infect animals. Some strains can also infect humans or evolve the ability to spread to humans.
- There are 7 known coronaviruses that infect people, including the newly discovered 2019 novel coronavirus (COVID-19 or 2019-nCoV, also known as Wuhan coronavirus), Middle East respiratory syndrome coronavirus (MERS-CoV), and severe acute respiratory syndrome coronavirus (SARS-CoV).
- MERS-CoV, SARS-CoV, and Wuhan coronavirus (2019-nCoV) made the news in recent years because they evolved and have the ability to spread from animals to humans and because they caused deaths.
- Researchers believe that MERS-CoV spread from camels in Saudi Arabia in 2012.
- Researchers believe that SARS-CoV spread from bats and civet cats in China in 2002.
- It is believed that an animal source of Wuhan coronavirus (COVID-19, 2019-nCoV) first infected humans at a market that sells live animals for food in Wuhan, Hubei Province, China, in 2019.
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