COVID-19
Coronavirus
This
article is about the group of viruses. For the disease involved in the 2019–20 coronavirus pandemic, see Coronavirus disease 2019. For the virus
that causes this disease, see Severe acute respiratorysyndrome coronavirus 2.
Coronaviruses are
a group of related viruses that cause diseases in mammals and birds. In humans,
coronaviruses cause respiratory tract infections that can
range from mild to lethal. Mild illnesses include some cases of the common cold (which
has other possible causes, predominantly rhinoviruses),
while more lethal varieties can cause SARS, MERS, and COVID-19. Symptoms in other species vary:
in chickens, they cause an upper respiratory tract disease,
while in cows and pigs they cause diarrhea.
There are yet to be vaccines or antiviral drugs to
prevent or treat human coronavirus infections.
Coronaviruses constitute the subfamily Orthocoronavirinae,
in the family Coronaviridae, order Nidovirales,
and realm Riboviria. They are envelopedviruses with a positive-sense single-stranded RNA genome and
a nucleocapsid of
helical symmetry. The genome size of coronaviruses ranges from approximately 26
to 32 kilobases, one of the largest among RNA viruses. They
have characteristic club-shaped spikes that
project from their surface, which in electronmicrographs create an image reminiscent of the solar corona from
which their name derives.
Discovery
Coronaviruses
were first discovered in the 1930s when an acute respiratory infection of
domesticated chickens was shown to be caused by infectious bronchitisvirus (IBV). Arthur
Schalk and MC Hawn described in 1931 a new respiratory infection of chickens in North Dakota.
The infection of new-born chicks was characterized by gasping and listlessness.
The mortality rate of the chicks was 40–90%. In 1937, Fred Beaudette and Charles
Hudson reported that they had successfully isolated and cultivated the
infectious bronchitis virus which caused the disease. In the 1940s, two more animal
coronaviruses, mouse hepatitis virus (MHV) and transmissible gastroenteritis virus (TGEV),
were isolated. It
was not realized at the time that these three different viruses were related.
Human
coronaviruses were discovered in the 1960s. The earliest ones studied were from
human patients with the commoncold, which were later named human coronavirus 229E and human coronavirus OC43. They
were first imaged by Scottish virologist June Almeida at
St. Thomas Hospital in London.
Other human coronaviruses have since been identified,
including SARS-CoV in 2003, HCoV NL63 in 2004, HK
serious respiratory tract infections.
Etymology
The name
"coronavirus" is derived from Latin corona, meaning "crown" or
"wreath", itself a borrowing from Greek κορώνη korṓnē, "garland, wreath". The
name was first used in 1968 by an informal group of virologists in the journal Nature to
designate the new family of viruses. The name refers to the characteristic
appearance of virions (the
infective form of the virus) by electron microscopy, which have a fringe of large,
bulbous surface projections creating an image reminiscent of a crown or of
a solar corona.
This morphology is created by the viral spike peplomers,
which are proteins on
the surface of the virus.
Precautions
Protect
yourself and others around you by knowing the facts and taking appropriate
precautions. Follow advice provided by your local public health agency.
To
prevent the spread of COVID-19, follow these steps :-
- Clean your hands often. Use soap and water, or an alcohol-based hand rub.
- Maintain a safe distance from anyone who is coughing or sneezing.
- Don’t touch your eyes, nose or mouth.
- Cover your nose and mouth with your bent elbow or a tissue when you cough or sneeze.
- Stay home if you feel unwell.
- If you have a fever, a cough, and difficulty breathing, seek medical attention. Call in advance.
Follow the directions of your local health
authority.
Avoiding
unneeded visits to medical facilities allows healthcare systems to operate more
effectively, therefore protecting you and others.
STAY HOME. SAVE LIVES.
Help stop coronavirus
- STAY home
- KEEP a safe distance
- WASH hands often
- COVER your cough
- SICK? Call the helpline
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