Coronavirus disease (COVID-19) is an infectious disease caused by the SARS-CoV-2 virus.
Most people infected with the virus will experience mild to moderate respiratory illness and recover without requiring special treatment. However, some will become seriously ill and require medical attention. Older people and those with underlying medical conditions like cardiovascular disease, diabetes, chronic respiratory disease, or cancer are more likely to develop serious illness. Anyone can get sick with COVID-19 and become seriously ill or die at any age.
The best way to prevent and slow down transmission is to be well informed about the disease and how the virus spreads. Protect yourself and others from infection by staying at least 1 metre apart from others, wearing a properly fitted mask, and washing your hands or using an alcohol-based rub frequently. Get vaccinated when it’s your turn and follow local guidance.
The virus can spread from an infected person’s mouth or nose in small liquid particles when they cough, sneeze, speak, sing or breathe. These particles range from larger respiratory droplets to smaller aerosols. It is important to practice respiratory etiquette, for example by coughing into a flexed elbow, and to stay home and self-isolate until you recover if you feel unwell.
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IN THIS ARTICLE
Where Did the Coronavirus Come From?
Coronavirus Evolution
Coronaviruses are a big family of different viruses. Some of them cause the common cold in people. Others infect animals, including bats, camels, and cattle. But how did SARS-CoV-2, the new coronavirus that causes COVID-19, come into being?
Here’s what we know about the virus that was first detected in Wuhan, China, in late 2019 and has set off a global pandemic.
Where Did the Coronavirus Come From?
Experts say SARS-CoV-2 originated in bats. That’s also how the coronaviruses behind Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS) got started.
SARS-CoV-2 made the jump to humans at one of Wuhan’s open-air “wet markets.” They’re where customers buy fresh meat and fish, including animals that are killed on the spot.
Some wet markets sell wild or banned species like cobras, wild boars, and raccoon dogs. Crowded conditions can let viruses from different animals swap genes. Sometimes the virus changes so much it can start to infect and spread among people.
Still, the Wuhan market didn’t sell bats at the time of the outbreak. That’s why early suspicion also fell on pangolins, also called scaly anteaters, which are sold illegally in some markets in China. Some coronaviruses that infect pangolins are similar to SARS-CoV-2.
As SARS-CoV-2 spread both inside and outside China, it infected people who have had no direct contact with animals. That meant the virus is transmitted from one human to another. It’s now spreading in the U.S. and around the globe, meaning that people are unwittingly catching and passing on the coronavirus. This growing worldwide transmission is what is now a pandemic.
Coronavirus Evolution
Scientists first identified a human coronavirus in 1965. It caused a common cold. Later that decade, researchers found a group of similar human and animal viruses and named them after their crown-like appearance.
Seven coronaviruses can infect humans. The one that causes SARS emerged in southern China in 2002 and quickly spread to 28 other countries. More than 8,000 people were infected by July 2003, and 774 died. A small outbreak in 2004 involved only four more cases. This coronavirus causes fever, headache, and respiratory problems such as cough and shortness of breath.
MERS started in Saudi Arabia in 2012. Almost all of the nearly 2,500 cases have been in people who live in or travel to the Middle East. This coronavirus is less contagious than its SARS cousin but more deadly, killing 858 people. It has the same respiratory symptoms but can also cause kidney failure.
Wiki
Etymology
During the initial outbreak in Wuhan, the virus and disease were commonly referred to as "coronavirus" and "Wuhan coronavirus",[19][20][21] with the disease sometimes called "Wuhan pneumonia".[22][23] In the past, many diseases have been named after geographical locations, such as the Spanish flu,[24] Middle East respiratory syndrome, and Zika virus.[25] In January 2020, the WHO recommended 2019-nCoV[26] and 2019-nCoV acute respiratory disease[27] as interim names for the virus and disease per 2015 guidance and international guidelines against using geographical locations (e.g. Wuhan, China), animal species, or groups of people in disease and virus names in part to prevent social stigma.[28][29][30] The official names COVID-19 and SARS-CoV-2 were issued by the WHO on 11 February 2020.[31] Tedros Adhanom explained: CO for corona, VI for virus, D for disease, and 19 for 2019 (the year in which the outbreak was first identified).[32] The WHO additionally uses "the COVID-19 virus" and "the virus responsible for COVID-19" in public communications.[31]
SARS-CoV-2 variants
Main article: Variants of SARS-CoV-2
The many thousands of SARS-CoV-2 variants are grouped into either clades or lineages.[73][74] The WHO, in collaboration with partners, expert networks, national authorities, institutions and researchers, have established nomenclature systems for naming and tracking SARS-CoV-2 genetic lineages by GISAID, Nextstrain and Pango. At the present time, the expert group convened by WHO has recommended the labeling of variants using letters of the Greek Alphabet, for example, Alpha, Beta, Delta, and Gamma, giving the justification that they "will be easier and more practical to discussed by non-scientific audiences."[75] Nextstraindivides the variants into five clades (19A, 19B, 20A, 20B, and 20C), while GISAID divides them into seven (L, O, V, S, G, GH, and GR).[76] The Pango tool groups variants into lineages, with many circulating lineages being classed under the B.1 lineage.[74][77]
Several notable variants of SARS-CoV-2 emerged throughout 2020.[78][79] Cluster 5 emerged among minks and mink farmers in Denmark.[80] After strict quarantines and a mink euthanasia campaign, the cluster was assessed to no longer be circulating among humans in Denmark as of 1 February 2021.[81]
As of July 2021, there are four dominant variants of SARS-CoV-2 spreading among global populations:
the Alpha Variant (formerly called the UK Variant and officially referred to as B.1.1.7), first found in London and Kent,
the Beta Variant (formerly called the South Africa Variant and officially referred to as B.1.351),
the Gamma Variant (formerly called the Brazil Variant and officially referred to as P.1), and
the Delta Variant(formerly called the India Variant and officially referred to as B.1.617.2).[82]
& Now Omicron Variant B.1.1.529 ( aka South African Variant and officially known as
& Now Omicron Variant B.1.1.529 ( aka South African Variant and officially known as
