Coronaviruses are types of viruses that typically affect the respiratory tracts of birds and mammals, including humans. The name "coronavirus" comes from the crown-like projections on their surfaces. "Corona" in Latin means "halo" or "crown".
Scientists first isolated a coronavirus in 1937, they found a coronavirus responsible for an infectious bronchitis virus in birds that had the ability to devastate poultry stocks. Members of the subfamily Coronavirus are widespread among mammals, often causing only mild respiratory or enteric infections. Over 60 coronaviruses (CoVs) have been isolated from bats (BtCoV) and most of these are in the genus betacoronavirus.
Diseases Caused by HCoVs
Human coronaviruses are typically responsible for common colds more than serious diseases. However, coronaviruses are also behind some more severe outbreaks such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS) and COVID-19.
SARS is a viral respiratory illness caused by a coronavirus, called SARS-associated coronavirus (SARS-CoV). Typically, it leads to a life threatening form of pneumonia. SARS was first reported in Asia in November 2002. Over the next few months, the illness spread to more than two dozen countries in North America, South America, Europe, and Asia before the SARS global outbreak of 2003 was contained .
According to the World Health Organization (WHO), a total of 8,098 people worldwide became sick with SARS during its outbreak. Of these, 774 infections were fatal. This equates to a mortality rate of 9.6%.
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, chills, diarrhea, breathlessness and aches. Pneumonia, a severe lung infection, usually develops. At its most advanced stage, SARS causes failure of the lungs, heart, or liver.
MERS spreads due to the coronavirus known as MERS-CoV. Scientists first recognized this severe respiratory illness in 2012 after it surfaced in Saudi Arabia. Since then, it has spread to other countries. MERS-CoV caused similar clinical symptoms as SARS-CoV but with a much higher mortality rate of about 35% .
Symptoms of MERS include fever, breathlessness, and coughing. The illness spreads through close contact with people who already have an infection. However, all cases of MERS have links to individuals recently returning from travel to the Arabian Peninsula.
In 2019, the Centers for Disease Control and Prevention (CDC) started monitoring the outbreak of a new coronavirus, SARS-CoV-2, which causes the respiratory illness now known as COVID-19. Symptoms vary from person-to-person with COVID-19. It may produce few or no symptoms. However, it can also lead to severe illness and may be fatal. Common symptoms include fever, breathlessness and cough. More information about COVID-19, please read 2019 Novel Coronavirus.
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