The coronavirus receives its name from the halo or crown (corona) that is seen when the virus is viewed by an electron microscope. This morphology is actually attributed to the glycoproteins the virus uses to attach to the host cell.
Coronaviruses (CoV) are a large family of viruses that cause illness ranging from the common cold to more severe diseases. Coronaviruses are zoonotic, meaning they are transmitted between animals and people. Detailed investigations found that SARS-CoV was transmitted from civet cats to humans and MERS-CoV from dromedary camels to humans. Several known coronaviruses are circulating in animals that have not yet infected humans.
During the auspicious time of Lunar New Year – the Spring festival of China, a deadly outbreak of coronavirus has engulfed the city of Wuhan, considered the epicenter of the epidemic which is home to over 11 million people.
So far, the virus has killed 81 people in China, and the confirmed cases rose sharply to 2,744 nationwide. As per the state media, the death of an 80-year-old woman in Hainan province is the first victim the outbreak has claimed.
Types of Coronaviruses
Different types of human coronaviruses vary in the severity of the illness they cause and how far they can spread.
There are currently six recognized types of coronavirus that can infect humans.
Common Human Coronaviruses
- 229E (alpha coronavirus)
- NL63 (alpha coronavirus)
- OC43 (beta coronavirus)
- HKU1 (beta coronavirus)
Other Human Coronaviruses
- MERS-CoV (the beta coronavirus that causes Middle East Respiratory Syndrome, or MERS)
- SARS-CoV (the beta coronavirus that causes the severe acute respiratory syndrome, or SARS)
- 2019 Novel Coronavirus (2019-nCoV)
People around the world commonly get infected with human coronaviruses 229E, NL63, OC43, and HKU1. Sometimes coronaviruses that infect animals can evolve and make people sick and become a new human coronavirus. Three recent examples of this are 2019-nCoV, SARS-CoV, and MERS-CoV.
- 2019 Novel Coronavirus (2019-nCoV)
On January 9, 2020, the World Health Organization reported that a novel (new) coronavirus was identified by Chinese authorities. The virus is associated with an outbreak of pneumonia in Wuhan City, Hubei Province, China.
Severe acute respiratory syndrome coronavirus (SARS-CoV) was first recognized in China in November 2002. It caused a worldwide outbreak in 2002-2003 with 8,098 probable cases including 774 deaths. Since 2004, there have not been any known cases of SARS-CoV infection reported anywhere in the world.
Middle East Respiratory Syndrome Coronavirus (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 or near the Arabian Peninsula. CDC continues to closely monitor MERS 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.
Fast facts about coronaviruses from the Centers for Disease Control.
- Scientists know of seven different coronaviruses that can infect people and make them sick.
- Most people get infected with at least one common human coronavirus at some point in their lives.
- Most human coronaviruses cause only mild to moderate illness in people worldwide.
- Symptoms often mimic the common cold or upper respiratory virus. They may include runny nose, headache, cough, sore throat, fever or a general feeling of being unwell.
- Infants, older adults and people with underlying medical issues and/or weakened immune systems are more likely to get lower-respiratory tract illnesses, such as pneumonia or bronchitis.
- The MERS (Middle East Respiratory Syndrome) coronavirus, first reported in 2012 in Saudi Arabia, caused severe acute respiratory illness in most patients. It spread to at least 25 countries but only two cases have been reported in the U.S. Both patients were healthcare workers who lived and worked in Saudi Arabia.
- SARS (severe acute respiratory syndrome) was another deadly coronavirus. It was first reported in Asia in 2003. It spread to more than two dozen countries in North America, South America, Europe and Asia, but was contained by 2004.
- There are currently no vaccines or specific treatments for illnesses caused by human coronaviruses. Researchers at UTMB in Galveston are working on a vaccine.
- Coronaviruses are common in many different species of animals, including camels and bats. Experts don’t understand why only certain coronaviruses are able to infect people.
The symptoms of most coronaviruses are similar to those of a common cold, including sneezing, stuffy or runny nose, sore throat, coughing, watery eyes, mild headache, and mild body aches. In the case of SARS, most patients develop a high fever that is sometimes associated with chills, headache, body aches and a general feeling of discomfort. After two to seven days, SARS patients may develop a dry, nonproductive cough which can lead to low oxygen levels in the blood. Most patients with SARS develop pneumonia.
Further investigation is required to assess whether there are undetected asymptomatic or mildly symptomatic cases.
How is it spread?
Early reports indicated that most of the cases had prior contact with seafood and live animal market, suggesting an animal source of the outbreak. However, more recently, human to human transmission has been reported.
Further investigation is underway to confirm and describe the mode of transmission from animal sources, and the risk of human-to-human transmission.
Human to human transmission is most likely to be through direct contact with infectious patients, by respiratory droplets and by fomites (contaminated objects and surfaces), as is seen with other coronavirus infections including SARS and MERS. The infectious droplets can also land on objects and surfaces where someone can then pick them up and touch his/her mouth, nose or eye(s).
Who is at risk?
People who are living or traveling to affected areas or who have had contact with other cases may be at risk of catching the disease. People with underlying illnesses that make them more vulnerable to respiratory disease, including those with diabetes, chronic lung disease, pre-existing kidney failure, people with suppressed immune systems and the elderly may be at a higher risk.
How is it diagnosed?
Infection with 2019-nCoV is diagnosed by finding evidence of the virus in respiratory samples such as swabs from the throat or fluid from the lungs. Testing for 2019-nCoV is done in public health laboratories.
How is the new coronavirus transmitted?
Although this coronavirus originally spread from animals to humans, it’s been confirmed that this strain of the virus can now spread between humans.
Similar to the common cold, the coronavirus is spread via droplets when a person coughs or sneezes.
How is it prevented?
It’s likely that general prevention measures used for other coronavirus infections will also prevent infection with 2019-nCoV.
The CDC is warning everyone to avoid any nonessential trips to Wuhan, and to avoid animals or sick people if you’re traveling elsewhere in China. If you’ve been to China in the last two weeks and experience any of the symptoms listed above, you should seek medical attention immediately—and you should call the doctor’s office or emergency room beforehand to let them know you’re coming.
The World Health Organization (WHO) recommends measures to reduce the general risk of acute respiratory infections while traveling in or from affected areas by:
- Avoiding close contact with people suffering from acute respiratory infections;
- Frequent hand-washing, especially after direct contact with ill people or their environment;
- Avoiding close contact with live or dead farm or wild animals;
- Travelers with symptoms of acute respiratory infection should practice cough etiquette (maintain distance, cover coughs and sneezes with disposable tissues or clothing, and wash hands).
Travelers to China are already advised not to visit live bird and animal markets, including ‘wet’ markets, due to the risk of avian influenza.
There is currently no vaccine to prevent 2019-nCoV infections.
Precautionary Measures; if returned from affected areas or have been in contact with a patient with coronavirus in the last 14 days?
If you become ill or feel unwell while traveling in China, you should not wait until you arrive back in Australia to seek medical assistance. Instead, you should see a doctor or go to the local emergency department.
If you develop a fever, a cough, a sore throat or shortness of breath within 14 days of travel or have had contact with a person with confirmed coronavirus, you should immediately isolate yourself from other people. Contact your GP or your emergency department and seek medical attention as soon as possible.
It is important to phone ahead so that the practice or emergency department can make appropriate preparations and protect others.
When seeking medical care wear a surgical mask (if possible) otherwise ask for one when you arrive.
What’s being done to stop the spread of the new coronavirus?
Steps are being taken to help stop the spread of the coronavirus. As of January 23, public transportation in Wuhan, China, and some surrounding areas— including buses, subways, and ferries— have been suspended.
Beijing has also canceled all large-scale New Year celebrations, which were slated to begin this weekend, to contain the spread of the virus.
Travel in and out of Wuhan, China and surrounding areas has been suspended. Those arriving from Wuhan to the U.S. and some other countries are being screened by health officials.
A combined population of more than 50 million people were under travel restrictions in China as of Monday.
If person-to-person transmission remains limited, then rapid isolation of patients and infection control in health facilities may stop the spread, as was successfully done with Severe Acute Respiratory Syndrome (SARS).