Coronavirus (CoV) is a family of viruses that can cause respiratory infection. First identified in the 1960s, they are categorized into four sub-groups, alpha, beta, gamma and delta. The illness caused by coronaviruses in humans can range from the mild common cold to more severe disease like COVID-19, which can be fatal.
Coronaviruses are named for the crown-like spikes that surround their surface. Corona is a Latin word that means “crown” or “wreath”.
What Causes Coronavirus Infection?
Common human coronaviruses are contagious and are easily spread from person to person. They are spread through close contact with someone who is infected via secretions from coughing and sneezing or touching objects that have the virus on them. In the United States, these coronaviruses are most likely to circulate during the fall and winter months.
Some coronaviruses are known to occur only in animals, including camels, cattle, cats, bats and rodents. A coronavirus that infects animals can evolve and infect people, and then start to spread from person to person. Such an infection that spreads from animals to people is said to “spillover.” This process is called zoonosis. Because humans have not built up any immunity to these new viruses, the illness they cause can be severe.
Symptoms of Coronavirus
Symptoms of coronavirus illness vary depending on the specific virus. Prior to the last two decades, the four coronaviruses known to affect humans were mild in the symptoms they caused. These included respiratory symptoms like a runny nose, headache, cough, sore throat, fever and fatigue. If an infection progresses to something more severe, it can cause pneumonia, bronchitis, organ failure and even death. This is more likely to happen in children, the elderly and people with weakened immune systems.
More recently, more severe coronavirus infections have caused concern worldwide. All three severe infections below are caused by a different betacoronavirus, which mainly are found in bats but can spill over into other species including humans.
- COVID-19 was first recognized in late 2019, caused by a coronavirus now called SARS-CoV-2. The number of cases has grown exponentially among people not exposed to these animals, confirming person-to-person transmission. With the spread of coronavirus disease to over 100 other locations, including the U.S., the World Health Organization (WHO) officially declared the outbreak a public health emergency and on March 11, 2020, a pandemic. For the first time in recorded history, a coronavirus has caused a pandemic.
Since then, the coronavirus has continued to exponentially spread across the globe via community spread, meaning individuals are becoming ill with the virus without any known contact to a sick individual.
- MERS was first identified in Saudi Arabia in 2012. The MERS virus causes flu-like symptoms, with most patients developing pneumonia. Around one-third of patients diagnoses with MERS have died, according to the CDC. MERS is still active, though uncommon, in the Middle East.
- SARS was a rapidly progressive respiratory illness that started in China in 2003 but spread worldwide before it was contained. Most people who contracted SARS had severe symptoms that required hospitalization. SARS was fatal for 1 in 10 patients, though most made a full recovery. There have been no cases of SARS anywhere in the world since 2004.
Treating and Preventing Coronaviruses
While COVID-19 is an exception, the majority of patients with milder coronavirus infections recover on their own without complications. They can be treated at home and take over-the-counter medication for symptoms such as fever and pain.
Similar to avoiding spreading other infections like the cold or the flu, coronaviruses are spread through contact. So the best way to protect from infection is to avoid touching people who are infected and wash your hands often. Try to avoid touching your eyes, nose and mouth. If you think you are infected, stay home and avoid crowds and contact with others. Keep others safe by covering your mouth when you cough or sneeze and disinfect the objects and surfaces you touch.
Published November 2, 2021
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