Introduction of corona virus
What
is a coronavirus?
A coronavirus is a type of RNA virus which can cause
illness in animals and people. Viruses break into cells inside their host and
use them to reproduce itself and disrupt the body's normal functions.
Coronaviruses are named after the Latin word 'corona', which means crown,
because they are encased by a spiked shell which resembles a royal crown.
Or
The name coronavirus comes from the Latin word corona, meaning
crown or halo. Under an electron microscope, the looks like it is surrounded by
a solar corona.
There
are four type of corona virus including alpha,beta,gamma and dalta whereas in
late 2019 China were identified as with a novel betacoronavirus, first called
the 2019 novel coronavirus (2019-nCov) and often referred to as the Wuhan
coronavirus. When the genomics of the 2019-nCov was sequenced, it shared 79.5%
of the genetic sequence of the SARS-CoV that caused the 2002–2003 pandemic and
the International Committee on Taxonomy of Viruses renamed the 2019-nCov as
SARS-CoV-2 The disease that the virus causes
has been named COVID-19, which stands for coronavirus disease 2019.
Dr Helena Maier, from the Pirbright Institute, said:
'Coronaviruses are a family of viruses that infect a wide range of different
species including humans, cattle, pigs, chickens, dogs, cats and wild
animals.
'Until this new coronavirus was identified, there were
only six different coronaviruses known to infect humans. Four of these cause a
mild common cold-type illness, but since 2002 there has been the emergence of
two new coronaviruses that can infect humans and result in more severe disease
(Severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome
(MERS) coronaviruses).
The new coronavirus, the seventh
known to affect humans, has been named COVID-19. Whereas other six are
MERS-COV,SARS-COV,NL63,229E,0C43 and HKU1. They all are usually similar as they
are found in animals and among all 7
'Coronaviruses are known to be able to occasionally jump
from one species to another and that is what happened in the case of SARS, MERS
and the new coronavirus. The animal origin of the new coronavirus is not yet
known
Coronaviruses are so named because their structure has jagged edges which look like a royal crown – corona is crown in Latin (Pictured, an illustration of the 2019-nCoV released by the US Centers for Disease Control and Prevention
The first person died that week and,
by January 16, two were dead and 41 cases were confirmed. The next day,
scientists predicted that 1,700 people had become infected, possibly up to
7,000.
History
of corona virus
It is believed that present pandemic
corona virus similar to past viruses known as SARS and MERS.
Again a similar virus appeared on
screen in 2012 known as MERS which transferred again from Bat to camel and than
affected 2494 people in which 858 people died.
Patients began to present in
November and December with various degrees of respiratory distress of unknown
etiology and treated at the time as possible influenza infections. As it became
apparent that most cases had a shared history of exposure to the Huanan Seafood
Wholesale Market (the so-called “wet market”), the Wuhan local health authority
issued an epidemiologic alert on 30 December 2019 and the wet market was
closed. About a week later, on 9 January 2020, Chinese researchers shared the
full genetic sequence of the novel coronavirus, now called SARS-CoV-2
Pathology
The SARS-related
coronaviruses are covered by spike proteins that contain a variable
receptor-binding domain (RBD). This RBD binds to angiotensin-converting
enzyme-2 (ACE-2) receptor found in the heart, lungs, kidneys, and
gastrointestinal tract. thus facilitating viral entry into target cells.
SARS-CoV to the angiotensin-converting enzyme
2 (ACE-2) receptors in the type II pneumocytes in the lungs triggers a cascade
of inflammation in the lower respiratory tract .
(A)
Spike
proteins on the surface of the coronavirus bind to angiotensin-converting
enzyme 2 (ACE-2) receptors on the surface of the target cell; (B) The
type II transmembrane serine protease (TMPRSS2) binds to and cleaves the ACE-2
receptor. In the process, the spike protein is activated; (C) Cleaved
ACE-2 and activated spike protein facilitate viral entry. TMPRSS2 expression
increases cellular uptake of the coronavirus
Viral entry and cell
infection trigger the host’s immune response, and the inflammatory cascade is
initiated by antigen-presenting cells (APC). The process starts with the APC
performing two functions: (1) presenting the foreign antigen to CD4+-T-helper
(Th1) cells, and (2) releasing interleukin-12 to further stimulate the Th1
cell. The Th1 cells stimulate CD8+-T-killer (Tk) cells
that will target any cells containing the foreign antigen. In addition,
activated Th1 cells stimulate B-cells to produce antigen-specific antibodies.
How deadly is it?
With more than 24,000
recorded deaths, the number of fatalities from the new coronavirus has
overwhelmingly surpassed the toll of the 2002-2003 SARS outbreak, which also
originated in China.
SARS killed about 9 percent
of those it infected - nearly 800 people worldwide and more than 300 in China
alone. MERS, which did not spread as widely, was more deadly, killing
one-third of those infected.
Much is still unknown, but COVID-19 seems to spread faster
than the 2003 SARS and also may cause less severe illness.
Experts have
been conflicted since the beginning of the outbreak about whether the true
number of people who are infected is significantly higher than the official
numbers of recorded cases. Some people are expected to have such mild symptoms
that they never even realise they are ill unless they're tested, so only the
more serious cases get discovered, making the death toll seem higher than it
really is.
However, an
investigation into government surveillance in China said it had found no reason
to believe this was true.
Dr Bruce
Aylward, a World Health Organization official who went on a mission to China,
said there was no evidence that figures were only showing the tip of the
iceberg, and said recording appeared to be accurate, Stat News reported.
Pandemics
It's important to note that seasonal flu, which causes outbreaks
every year, should not be confused with pandemic flu, or a global outbreak of a new flu virus that is very different
from the strains that typically circulate. This happened in 2009 with the swine
flu pandemic, which is estimated to have killed between 151,000 and 575,000
people worldwide, according to the CDC. There is no flu pandemic happening
currently.
On March 11, the World Health Organization (WHO) officially
declared the outbreak of COVID-19 a pandemic. This is the first time WHO has declared a pandemic over
a coronavirus.
Where
did it come from?
China alerted the WHO to
cases of unusual pneumonia in Wuhan on December 31.
COVID-19 is thought to
have originated in a seafood market where wildlife was sold illegally.
The first cases of COVID-19 came from
people visiting or working in a live animal market in Wuhan, which has since
been closed down for investigation.
Although the market is officially a seafood
market, other dead and living animals were being sold there, including wolf
cubs, salamanders, snakes, peacocks, porcupines and camel meat.
A study by the Wuhan Institute of
Virology, published in February 2020 in the scientific journal Nature, found
that the genetic make-up virus samples found in patients in China is 96 per
cent identical to a coronavirus they found in bats.
However, there were not many bats at the
market so scientists say it was likely there was an animal which acted as a
middle-man, contracting it from a bat before then transmitting it to a human.
It has not yet been confirmed what type of animal this was.
HOW COVID-19 SPREADS
– CAUSES OF CORONAVIRUS
Person-to-person spread through respiratory
tract
The virus is thought to
spread mainly from person-to-person.
The virus that causes
COVID-19 is mainly transmitted through droplets generated when an infected
person coughs, sneezes, or speaks. These droplets are too heavy to hang
in the air. They quickly fall on floors or surfaces.
You can be infected by
breathing in the virus if you are within 1 metre of a person who has COVID-19,
or by touching a contaminated surface and then touching your eyes, nose or
mouth before washing your hands.
What
are the symptoms?
Reported illnesses have
ranged from mild symptoms to severe illness and death for confirmed coronavirus
disease 2019 (COVID-19) cases.
The following symptoms
may appear 2-14 days after exposure.as it is contagious disease so
before even symptoms appear it already affected others.
·
Fever
·
Cough
·
Shortness of breath
If you develop emergency
warning signs for COVID-19 get medical attention immediately.
Emergency warning signs include*:
·
Trouble breathing
·
Persistent pain or
pressure in the chest
·
New confusion or
inability to arouse
·
Bluish lips or face
*This list is not all
inclusive. Please consult your medical provider for any other symptoms that are
severe or concerning.
In more
severe cases, it can lead to pneumonia, multiple organ failure and even death.
However,
infected patients can also be asymptomatic, meaning they do not display any
symptoms despite having the virus in their systems.
The vast majority of patients will recover
from milder symptoms without any issues, and many will need no medical help at
all.
In a small group of patients, who seem
mainly to be the elderly or those with long-term illnesses, it can lead to
pneumonia.
COVID-19 is a new
disease and there is limited information regarding risk factors for severe
disease. Based on currently available information and clinical expertise, older
adults and people of any age who have serious underlying medical
conditions might be at higher risk for severe illness from COVID-19.
Based upon available information
to date, those at high-risk for severe illness from COVID-19 include:
·
People who live in a
nursing home or long-term care facility
·
Other high-risk
conditions could include:
o People with chronic lung disease or moderate to
severe asthma
o People who have serious heart conditions
o People who are immunocompromised including
cancer treatment
o People of any age with severe obesity (body mass
index [BMI] >40) or certain underlying medical conditions,
particularly if not well controlled, such as those with diabetes, renal
failure, or liver disease might also be at risk
·
People who are pregnant
should be monitored since they are known to be at risk with severe viral
illness, however, to date data on COVID-19 has not shown increased risk
Many conditions can
cause a person to be immunocompromised, including cancer treatment, smoking,
bone marrow or organ transplantation, immune deficiencies, poorly controlled
HIV or AIDS, and prolonged use of corticosteroids and other immune weakening
medications
Page last reviewed: March 26, 2020
Content source: National Center for Immunization and Respiratory Diseases
(NCIRD), Division of Viral Diseases
What
have genetic tests revealed about the virus?
Scientists
in China have recorded the genetic sequences of around 19 strains of the virus
and released them to experts working around the world.
This
allows others to study them, develop tests and potentially look into treating
the illness they cause.
Examinations
have revealed the coronavirus did not change much – changing is known as
mutating – much during the early stages of its spread.
However,
the director-general of China's Center for Disease Control and Prevention, Gao
Fu, said the virus was mutating and adapting as it spread through people.
This
means efforts to study the virus and to potentially control it may be made
extra difficult because the virus might look different every time scientists
analyse it.
More
study may be able to reveal whether the virus first infected a small number of
people then change and spread from them, or whether there were various versions
of the virus coming from animals which have developed separately.
How
is COVID-19 diagnosed?
Diagnosis may be difficult with only a physical
exam because mild cases of COVID-19 may appear similar to the flu or a bad
cold. A laboratory test can confirm the diagnosis
Viral
pneumonias typically do not result in the production of purulent sputum. Thus,
a nasopharyngeal swab is usually the collection method used to obtain a
specimen for testing. Nasopharyngeal specimens may miss some infections; a
deeper specimen may need to be obtained by bronchoscopy. Alternatively,
repeated testing can be used because over time, the likelihood of the
SARS-CoV-2 being present in the nasopharynx increases.
Treatment
of corona virus?
The
COVID-19 virus cannot be cured and it is proving difficult to contain.
Antibiotics
do not work against viruses, so they are out of the question. Antiviral drugs
can work, but the process of understanding a virus then developing and
producing drugs to treat it would take years and huge amounts of money.
No
vaccine exists for the coronavirus yet and it's not likely one will be
developed in time to be of any use in this outbreak, for similar reasons to the
above.
Currently,
governments and health authorities are working to contain the virus and to care
for patients who are sick and stop them infecting other people.
People
who catch the illness are being quarantined in hospitals, where their symptoms
can be treated and they will be away from the uninfected public.
And
airports around the world are putting in place screening measures such as
having doctors on-site, taking people's temperatures to check for fevers and
using thermal screening to spot those who might be ill (infection causes a
raised temperature).
However,
it can take weeks for symptoms to appear, so there is only a small likelihood
that patients will be spotted up in an airport.
Currently, however,
there is no cure for this coronavirus, and treatments are based on the kind of
care given for influenza (seasonal flu) and other severe respiratory illnesses,
known as "supportive care," according to the Centers for Disease
Control and Prevention (CDC). These treatments essentially treat the symptoms,
which often in the case of COVID-19 involve fever, cough and shortness of breath.
In mild cases, this might simply mean rest and fever-reducing medications such
as acetaminophen (Tylenol) for
comfort.
In hospitals, doctors and nurses are sometimes treating COVID-19
patients with the antiviral drug
oseltamivir, or Tamiflu, which seems to suppress the virus' reproduction in at least
some cases. This is somewhat surprising, Michigan Tech virologist Ebenezer
Tumban told Live Science, as Tamiflu was designed to target an enzyme on the
influenza virus, not on coronaviruses. The National Institutes of Health has
begun a clinical trial at the University of Nebraska Medical Center to test the
antiviral remdesivir for COVID-19, the agency announced Feb. 25. In China, doctors are also testing an array
of other antivirals originally designed to treat Ebola and HIV, Nature Biotechnology reported.
In cases in which pneumonia inhibits breathing, treatment
involves ventilation with oxygen. Ventilators blow air into the lungs through a
mask or a tube inserted directly into the windpipe. A New England Journal of Medicine study of 1,099 hospitalized patients with the
coronavirus in China found that 41.3% needed supplemental oxygen and 2.3%
needed invasive mechanical ventilation. Glucocorticoids were given to 18.6% of
patients, a treatment often used to reduce inflammation and help open airways
during respiratory disease.
HOW ARE PUBLIC HEALTH SYSTEMS REACTING
TO THE COVID-19 PANDEMIC?
The
COVID-19 pandemic is a tremendous test for public health systems all around the
world. How are they responding to this ongoing emergency? As a result of the
rapid proliferation of COVID-19, the coronavirus public health response has
included the issuing of recommendations to cancel just about every gathering of
more than 10 people, including religion services and special events. Officials
and leaders around the world are striving to be proactive to issue coronavirus
public health response recommendations ahead of a potential crisis situation.
Schools in cities and suburbs around the world have been canceled, with many
campuses enabling online, distance learning. Many people are working from home,
if they can, which presents its own challenges, especially if schools and child
care centers are closed. The coronavirus public health emergency has caused the
DOW stock exchange to plummet, and those who work in restaurant and retail
industries are experiencing a sharp drop in business. No doubt, we will
continue to see effects of the coronavirus public health emergency for months
and years to come.
WHO IS WORKING ON A
COVID-19 VACCINE?
There
are various impactful vaccines currently in widespread use throughout the world
to prevent infectious disease including the measles, MMR, mumps, rubella, and
flu. Surely, at some point in the hopefully not-to-distant future, there will
be a vaccine for COVID-19. Scientists throughout the world are working together
and rushing to develop an effective COVID-19 vaccine to put the public’s fears
at ease and prevent the number of deaths because of novel coronavirus infection
from continuing to mount. However, because of the time-consuming nature of
vaccine development, clinical trials, and implementation, it’s highly unlikely
that a COVID-19 will be available to the public within a year. Clinical trials
alone usually take at least 12 months to complete. Government approval
processes can also be lengthy and time-consuming, but it’s worth it in order to
ensure the vaccine is totally safe and effective for public use.
There is no vaccine for the coronavirus that causes COVID-19.
Scientists are working to develop one, Hilary Marston, a medical officer and
policy advisor at the National Institute of Allergy and Infectious Diseases
(NIAID), said in a Harvard T.H. Chan School of Public Health
webcast on Monday (March
2).
As of March 14, doctors in Seattle are recruiting volunteers to
participate in a clinical trial for an experimental vaccine for COVID-19 that's
being developed by the biotechnology company Moderna Therapeutics. However, biomedical
ethicists are concerned that a critical step in vaccine development was
skipped. In order to fast-track the vaccine, the researchers didn’t first show
that it triggered an immune response in animals, a step that is normally
required before human testing, Live Science previously reported.
The researchers did begin testing the experimental vaccine on
lab mice on the same day they started recruiting people for the clinical
trial, Stat News reported. The mice did show an immune response that
was similar to the one triggered by an experimental vaccine for a related
coronavirus MERS-CoV. (Vaccines work by priming your immune system to recognize
a virus like SARS-CoV-2 as an enemy and put up an attack against it.)
Even so, doctors aren't sure how much this
"fast-tracking" will speed up the time it takes to develop and bring
such a vaccine to market.
Before this experimental vaccine was in the works, Marston had
said not to expect a vaccine in the near term. "If everything moves as
quickly as possible, the soonest that it could possibly be is about
one-and-a-half to two years. That still might be very optimistic," Marston
said.
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