Coronaviruses are a group of viruses that cause diseases in mammals and birds. In humans, the viruses cause respiratory infections which are typically mild including the common cold but rarer forms like SARS and MERS can be lethal. In cows and pigs, they may cause diarrhea, while in chickens they can cause an upper respiratory disease. There are no vaccines or antiviral drugs that are approved for prevention or treatment.
Coronaviruses are viruses in the subfamily Orthocoronavirinae in the family Coronaviridae, in the order Nidovirales. Coronaviruses are enveloped viruses with a positive-sense single-stranded RNA genome and with a nucleocapsid of helical symmetry. The genomic size of coronaviruses ranges from approximately 26 to 32 kilobases, the largest for an RNA virus.
The name “coronavirus” is derived from the Latin corona, meaning crown or halo, which refers to the characteristic appearance of the virus particles (virions): they have a fringe reminiscent of a royal crown or the solar corona.
A coronavirus is a kind of common virus that causes an infection in your nose, sinuses, or upper throat. Most coronaviruses are not dangerous.
Some types of coronaviruses are serious, though. About 858 people have died from Middle East respiratory syndrome (MERS), which first appeared in 2012 in Saudi Arabia and then in other countries in the Middle East, Africa, Asia, and Europe. In April 2014, the first American was hospitalized for MERS in Indiana and another case was reported in Florida.
Both had just returned from Saudi Arabia. In May 2015, there was an outbreak of MERS in Korea, which was the largest outbreak outside of the Arabian Peninsula. In 2003, 774 people died from a severe acute respiratory syndrome (SARS) outbreak. As of 2015, there were no further reports of cases of SARS.
But In early 2020, following a December 2019 outbreak in China, the World Health Organization identified a new type, 2019 novel coronavirus (2019-nCoV).
On 31 December 2019, WHO was alerted to several cases of pneumonia in Wuhan City, Hubei Province of China. The virus did not match any other known virus. This raised concern because when a virus is new, we do not know how it affects people.
One week later, on 7 January, Chinese authorities confirmed that they had identified a new virus. The new virus is a coronavirus, which is a family of viruses that include the common cold, and viruses such as SARS and MERS. This new virus was temporarily named “2019-nCoV.”
2019 Novel Coronavirus
In 2019, the Centers for Disease Control and Prevention (CDC) started monitoring the outbreak of a new coronavirus. Authorities first identified the virus in Wuhan, China. They have named it the 2019 Novel Coronavirus (2019-nCov).
More than 1,000 people have contracted the virus in China. Health authorities have identified several other people with 2019-nCov around the world, including five individuals in the United States.
Some of the first people with 2019-nCov had links to an animal and seafood market. This initially suggested that animals transmit the virus to humans. However, people with a more recent diagnosis had no connections with or exposure to the market, suggesting that humans can pass the virus to each other.
Information on the virus is scarce at present. While the virus is not yet transmitting between humans in the U.S., it is likely to occur. In the past, respiratory conditions that develop from coronaviruses, such as SARS and MERS, have spread through close contacts.
However, while some viruses are highly contagious, it is less clear with coronaviruses as to how rapidly they will spread. At present, the CDC considers 2019-nCov to be a low risk for people in the U.S.
No vaccine is currently available for 2019-nCov. However, scientists in China and now Australia have replicated the virus. This could allow for early detection and treatment in people who have the virus but are not yet showing symptoms.
WHO has been working with Chinese authorities and global experts from the day we were informed, to learn more about the virus, how it affects the people who are sick with it, how they can be treated, and what countries can do to respond.
Because this is a coronavirus, which usually causes respiratory illness, WHO has advised to people on how to protect themselves and those around them from getting the disease.
Often a coronavirus causes upper respiratory infection symptoms like a stuffy nose, cough, and sore throat. You can treat them with rest and over-the-counter medication. The coronavirus can also cause middle ear infections in children.
First Time Detection Coronavirus
Coronaviruses were discovered in the 1960s:- the earliest ones discovered were infectious bronchitis virus in chickens and two viruses from the nasal cavities of human patients with the common cold that were subsequently named human coronavirus 229E and human coronavirus OC43.
Other members of this family have since been identified, including SARS-CoV in 2003, HCoV NL63 in 2004, HKU1 in 2005, MERS-CoV in 2012, and 2019-nCoV in 2019; most of these have been involved in serious respiratory tract infections.
What Is SARS?
Severe acute respiratory syndrome (SARS) was a contagious disease caused by the SARS-CoV coronavirus. It typically led to a life-threatening form of pneumonia.
The virus started off in the Guangdong Province in southern China in November 2002, eventually reaching Hong Kong. From there, it rapidly spread around the world, infecting people in 37 countries.
SARS-CoV is unique. It can infect both the upper and lower respiratory tract and can also cause gastroenteritis.
The symptoms of SARS develop over the course of a week and start with a fever. Early on in the condition, people develop flu-like symptoms, such as:
- dry coughing
Pneumonia, a severe lung infection, may develop afterward. At its most advanced stage, SARS causes failure of the lungs, heart, or liver.
During the epidemic, there were 8,098 confirmed cases of SARS with 774 fatalities. This is equal to a mortality rate of 9.6 percent. Complications were more likely in older adults, and half of all infected people over the age of 65 years who became ill did not survive. It was eventually brought under control in July 2003.
What Is MERS?
MERS, caused by the MERS-CoV coronavirus, was first recognized in 2012. This severe respiratory illness first surfaced in Saudi Arabia and, since then, has spread to other countries. The virus has reached the U.S., and the largest outbreak outside the Arabian Peninsula occurred in South Korea in 2015.
Symptoms include fever, breathlessness, and coughing. The illness spreads through close contact with people who have already been infected. However, all cases of MERS are linked to individuals who have recently returned from travel to the Arabian Peninsula. MERS is fatal in 30 to 40 percent of people who contract it.
What Is a Coronavirus?
Coronaviruses were first identified in the 1960s, but we don’t know where they come from. They get their name from their crown-like shape. Sometimes, but not often, a coronavirus can infect both animals and humans.
Most coronaviruses spread the same way other cold-causing viruses do: through infected people coughing and sneezing, by touching an infected person’s hands or face, or by touching things such as doorknobs that infected people have touched.
Almost everyone gets a coronavirus infection at least once in their life, most likely as a young child. In the United States, coronaviruses are more common in the fall and winter, but anyone can come down with a coronavirus infection at any time.
Types Of Coronavirus
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 types include:
- 229E (alpha coronavirus)
- NL63 (alpha coronavirus)
- OC43 (beta coronavirus)
- HKU1 (beta coronavirus)
Rarer, more dangerous types include MERS-CoV, which causes Middle East Respiratory Syndrome (MERS), and severe acute respiratory syndrome (SARS-CoV), the coronavirus responsible for SARS.
Coronaviruses are a group of common viruses. They are named for the crown-like spikes on the surface of the virus. Some coronaviruses only affect animals, but others can also affect humans. Most people get infected with human coronaviruses at some time in their life.
This usually causes mild to moderate upper-respiratory infections, like the common cold. But they can also cause more severe illnesses such as bronchitis and pneumonia.
There are several different types of human coronaviruses, including the 2019 Novel Coronavirus (2019-nCoV) and the Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS) coronaviruses.
How are coronavirus infections spread?
Human coronaviruses usually spread from an infected person to others through
- Coughing and sneezing without covering the mouth can disperse droplets into the air, spreading the virus.
- Rarely, feces (poop)
- Touching or shaking hands with a person that has the virus can pass the virus from one person to another.
- Making contact with a surface or object that has the virus and then touching your nose, eyes, or mouth.
- Touching an object or surface with the virus on it, then touching your mouth, nose, or eyes before washing your hands
- On rare occasions, a coronavirus may spread through contact with feces.
People in the U.S. are more likely to contract the disease in the winter or fall. The disease is still active during the rest of the year.
Young people are most likely to contract a coronavirus, and people can contract more than one infection over the course of a lifetime. Most people will become infected with at least one coronavirus in their life.
Risk of coronavirus infections?
Anyone can get a coronavirus infection, but young children are most likely to get infected. In the United States, infections are more common in the fall and winter.
Symptoms of Coronavirus
The symptoms of most coronaviruses are similar to any other upper respiratory infection, including runny nose, coughing, sore throat, and sometimes a fever. In most cases, you won’t know whether you have a coronavirus or a different cold-causing virus, such as rhinovirus.
You could get lab tests, including nose and throat cultures and blood work, to find out whether your cold was caused by a coronavirus, but there’s no reason to. The test results wouldn’t change how you treat your symptoms, which typically go away in a few days.
But if a coronavirus infection spreads to the lower respiratory tract (your windpipe and your lungs), it can cause pneumonia, especially in older people, people with heart disease, or people with weakened immune systems.
Common human coronaviruses
Common human coronaviruses, including types 229E, NL63, OC43, and HKU1, usually cause mild to moderate upper-respiratory tract illnesses, like the common cold. Most people get infected with these viruses at some point in their lives.
Cold- or flu-like symptoms usually set in from two to four days after coronavirus infection, and they are typically mild. These illnesses usually only last for a short amount of time. Symptoms may include
- runny nose
- a cough
- in rare cases,
- exacerbated asthma
- sore throat
- a general feeling of being unwell
Some coronaviruses can cause severe symptoms. The infections may turn into bronchitis and pneumonia, which cause symptoms such as
- Fever, which may be quite high if you have pneumonia
- Cough with mucus
- Shortness of breath
- Chest pain or tightness when you breathe and cough
Severe infections are more common in people with heart or lung diseases, people with weakened immune systems, infants, and older adults.
Human coronaviruses can sometimes cause lower-respiratory tract illnesses, such as pneumonia or bronchitis. This is more common in people with cardiopulmonary disease, people with weakened immune systems, infants, and older adults.
Other Human Coronaviruses
Two other human coronaviruses, MERS-CoV and SARS-CoV have been known to frequently cause severe symptoms. MERS symptoms usually include fever, cough, and shortness of breath which often progress to pneumonia. About 3 or 4 out of every 10 patients reported with MERS have died.
MERS cases continue to occur, primarily in the Arabian Peninsula. SARS symptoms often included fever, chills, and body aches which usually progressed to pneumonia. No human cases of SARS have been reported anywhere in the world since 2004.
Your healthcare provider may order laboratory tests on respiratory specimens and serum (part of your blood) to detect human coronaviruses. Laboratory testing is more likely to be used if you have severe disease or are suspected of having MERS.
If you are experiencing symptoms, you should tell your healthcare provider about any recent travel or contact with animals. Most MERS-CoV infections have been reported from countries in the Arabian Peninsula. Therefore reporting a travel history or contact with camels or camel products is very important when trying to diagnose MERS.
To make a diagnosis, your health care provider will
- Take your medical history, including asking about your symptoms
- Do a physical exam
- May do blood tests
- May do lab tests of sputum, a sample from a throat swab, or other respiratory specimens
What to Do About Coronavirus
There is no vaccine for coronavirus. To help prevent a coronavirus infection, do the same things you do to avoid the common cold:
- Wash your hands thoroughly with soap and warm water or with an alcohol-based hand sanitizer.
- Keep your hands and fingers away from your eyes, nose, and mouth.
- Avoid close contact with people who are infected.
You treat a coronavirus infection the same way you treat a cold:
- Get plenty of rest.
- Drink fluids.
- Take over-the-counter medicine for a sore throat and fever. But don’t give aspirin to children or teens younger than 19; use ibuprofen or acetaminophen instead.
A humidifier or steamy shower can also help ease a sore and scratchy throat.
Even when a coronavirus causes MERS or SARS in other countries, the kind of coronavirus infection common in the U.S. isn’t a serious threat for an otherwise healthy adult. If you get sick, treat your symptoms and contact a doctor if they get worse or don’t go away.
How to Protect Yourself?
WHO’s standard recommendations for the general public to reduce exposure to and transmission of a range of illnesses are as follows, which include hand and respiratory hygiene, and safe food practices:
- Frequently clean hands by using alcohol-based hand rub or soap and water;
- When coughing and sneezing cover mouth and nose with flexed elbow or tissue – throw the tissue away immediately and wash hands;
- Avoid close contact with anyone who has a fever and cough;
- If you have a fever, cough and difficulty breathing seek medical care early and share previous travel history with your health care provider;
- When visiting live markets in areas currently experiencing cases of a novel coronavirus, avoid direct unprotected contact with live animals and surfaces in contact with animals;
- The consumption of raw or undercooked animal products should be avoided. Raw meat, milk or animal organs should be handled with care, to avoid cross-contamination with uncooked foods, as per good food safety practices.
Treatments of coronavirus infections
There are no specific treatments for coronavirus infections. Most people will get better on their own. However, you can relieve your symptoms by
- Taking over-the-counter medicines for pain, fever, and cough. However, do not give aspirin to children. And do not give cough medicine to children under four.
- Using a room humidifier or taking a hot shower to help ease a sore throat and cough
- Getting plenty of rest
- Drinking fluids
Human coronaviruses cannot be cultivated in the laboratory easily, unlike the rhinovirus, another cause of the common cold. This makes it difficult to gauge the coronavirus impact on national economies and public health.
There is no cure, so treatments include taking care of yourself and over-the-counter (OTC) medication:
- Rest and avoid overexertion.
- Drink enough water.
- Avoid smoking and smoky areas.
- Take acetaminophen, ibuprofen or naproxen to reduce pain and fever.
- Use a clean humidifier or cool mist vaporizer.
The virus responsible can be diagnosed by taking a sample of respiratory fluids, such as mucus from the nose, or blood.
Prevented from coronavirus infections
Right now, there aren’t any vaccines to prevent human coronavirus infections. But you may able to reduce your risk of getting or spreading an infection by
- Washing hands often with soap and water for at least 20 seconds
- Avoiding touching your face, nose, or mouth with unwashed hands
- Avoiding close contact with people who are sick
- Cleaning and disinfecting surfaces that you frequently touch
- Covering coughs and sneezes with a tissue. Then throw away the tissue and wash your hands.
- Staying home when sick