Coronaviruses are a large family of viruses that are known to cause illness ranging from the common cold to more severe diseases such as Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS).
A novel coronavirus (COVID-19) was identified in 2019 in Wuhan, China. This is a new coronavirus that has not been previously identified in humans. im mentioned in this ppt about Coronavirus disease symptoms, transmission, mechanism, treatment, diagnosis etc.
2. CONTENTS
What is coronavirus
History of coronavirus
Taxonomy
Mechanism
Symptoms
Transmission
Prevention & control
Diagnosis
Treatment
Conclusion
References
3. What is coronavirus
The virus that causes COVID-19 is thought to have originated in
bats and then spread to snakes and pangolins and hence to humans,
perhaps by contamination of meat from wild animals.
Coronavirus disease 2019 (COVID-19) is a new virus strain
spreading from person to person & it is respiratory illness that can
spreading rapidly.
Type of virus that affects the respiratory tract. This group of viruses
are associated with the common cold, pneumonia, and severe acute
respiratory syndrome (SARS), and more severe cases can cause death.
The SARS-CoV-2 is a β-coronavirus, which is enveloped non-
segmented positive-sense RNA virus (subgenus sarbecovirus,
Orthocoronavirinae subfamily) Coronaviruses (CoV) are divided into
four genera, including α−/ β−/γ−/δ-CoV. α- and β-CoV are able to
infect mammals.
4. Coronaviruses are single-
stranded RNA viruses, about
120 nanometers in diameter.
While SARS-CoV and MERS-
CoV have positive-sense RNA
genomes of 27.9kb and 30.1kb.
It has been shown that the
genome of CoVs contains a
variable number (6–11) of open
reading frames (ORFs). The rest
part of the virus genome
encodes four essential structural
proteins, including spike
(S)glycoprotein, small envelope
protein,matrix.
protein, and nucleocapsid protein, and also several accessory proteins.
SglycoproteinofSARS-CoV-2binds to host cell receptors, angio tensin-
converting enzyme2 (ACE2), that is a critical step for virus entry. Two-thirds
of viral RNA, mainly located in the first ORF (ORF1a/b) translates two poly
proteins, pp1a and pp1ab, and encodes 16 non-structural proteins (NSP)
5. History of coronavirus
Coronaviruses were first discovered in the 1930s when an acute respiratory infection
of domesticated chicken was shown caused by infection bronchitis virus.
Arthur schalk & Mc hawn described in 1931 a respiratory infection of chickens in
north dakota.
Human coronaviruses were discovered in 1960s. Where observed some symptoms
common cold, fever etc, which were later named human coronavirus 229E & human
coronavirus OC43.
Human Coronavirus (B814) was obtained from boy with common cold in 1965by
Tyrell & Bynoe.
The early in 31 December 2019, new coronavirus (SARV co-2) was observed in
seafood live animal market at Wuhan city, china.
In December 2019, a cluster of pneumonia cases, caused by a newly identified β-
coronavirus, occurred in Wuhan.
6. Taxonomy
The scientific name for coronavirus
is Orthocoronavirinae or Coronavirinae. Coronaviruses belong to the
family of Coronaviridae, order Nidovirales, and realm Riboviria. They
are divided into alphacoronaviruses and betacorona viruses which infect
mammals – and gammacorona viruses and deltacorona viruses which
primarily infect birds.
Genus
Alphacoronaviruses (Alpha-CoV) are the first of the four genera, Alpha-,
Beta-, Gamma and Deltacoronavirus in the subfamily Coronavirinae of
the family Coronaviridae. Betacoronaviruses are one of four genera of
coronaviruses of the subfamily Orthocoronavirinae in the
family Coronaviridae, of the order Nidovirales
7. Mechanism
The corona-like appearance of coronaviruses is caused by so-called spike
glycoproteins, or peplomers, which are necessary for the viruses to enter host
cells.
The spike has two subunits; one subunit, S1, binds to a receptor on the
surface of the host’s cell; the other subunit, S2, fuses with the cell membrane.
The cell membrane receptor for both SARS-CoV-1 and SARS-CoV-2 is a
form of angiotensin converting enzyme, ACE-2, different from the enzyme
that is inhibited by conventional ACE-1 inhibitors, such as enalapril and
ramipril.
the S1 subunit of the spike binds to the ACE-2 enzyme on the cell
membrane surface. A host transmembrane serine protease, TMPRSS2, then
activates the spike and cleaves ACE-2. TMPRSS2 also acts on the S2
subunit, facilitating fusion of the virus to the cell membrane. The virus then
enters the cell. Inside the cell the virus is released from endosomes by
acidification or the action of an intracellular cysteine protease, cathepsin
8. The virus can enter the cell in two ways:(a) A cell membrane-bound
serine protease (brown), TMPRSS2, cleaves the virus’s S1 subunits (red)
from its S2 subunits (black) and also cleaves the ACE-2 enzymes; the
endosome enters the cell (endocytosis), where the virus is released by
acidification or the action of another protease, cathepsin(b) The same
serine protease, TMPRSS2, causes irreversible conformational changes in
the virus’s S2 subunits, activating them, after which the virus fuses to the
cell membrane and can be internalized by the cell.
9. Symptoms
Patient with COVID-19 have had mild to severe
respiratory illness with Symptoms of
Fever
Cough
Shortness of breath & difficulty breathing
Headache
Runny nose
Body aches
Malaise – a general feeling of being unwell
Sore throat
10. Transmission
The virus that causes COVID-19 probably emerged from an
animal source, but is now spreading from person to person.
The virus is thought to spread mainly between people who are
in close contact with one another (within about 6 feet) through
respiratory droplets produced when an infected person coughs
or sneezes.
It also may be possible that a person can get COVID-19 by
touching a surface or object that has the virus on it and then
touching their own mouth, nose, or possibly their eyes, but this
is not thought to be the main way the virus spreads.
11. Person-to-person transmission occurs primarily via direct contact
or through droplets spread by coughing or
sneezing from an infected individual. In a small study conducted
on women in their third trimester who were confirmed to be
infected with the coronavirus, there was no evidence that there is
transmission from mother to child.
12. Prevention & control
Wash hands thoroughly with soap and water for at least 20 seconds.
Avoid using your clean hands to turn off water or open the door. OR you may
use hand-sanitizer with at least 60% alcohol base.
Avoid touching your eyes, nose, or mouth with unwashed hands
Wear a mask while out in public, especially when traveling on an airplane o The
most effective, freely available mask is the 3M N95 which must be worn with no
leakage. Single layer masks are not effective.
Avoid close contact with people who are sick
Wear a mask to prevent virus transmission through sneezing and coughing
Clean and disinfect objects and surfaces
13. If presenting with symptoms, see your primary physician for further evaluation
Rest is extremely important, do NOT participate in fitness training
During the infectious stage (14 days), follow Standard Precautions outlined by
local/national/international health authorities
Once past the infectious stage (14 days) limit going to and from public places
only as you risk increasing the transmission of the virus to others and delays your
recovery time.
14. Diagnosis
The basis of diagnosis for new viruses is the reverse transcriptase–
polymerase chain reaction (RT-PCR) test used to identify genetic
material in many clinical samples. The CDC developed a protocol
for RT-PCR that included specific primers designed to bind to key
areas of the novel coronavirus. FDA authorized CDC’s test via an
Emergency Use Authorization (EUA),2 through which the FDA
permits use of a non–FDA-approved drug or device to respond to a
declared emergency.
15. Treatment
There is no specific antiviral treatment for COVID-19. but treatment is
doing depends on symptoms of disease. Use as systemic corticosteroid
treatment including neuraminidase inhibitors (oseltamivir, peramivir,
zanamivir, etc), ganciclovir, acyclovir, and ribavirin, as well as
methylprednisolone
Another report showed that the broad-spectrum antiviral remdesivir and
chloroquine are highly effective in the control of 2019- nCoV infection in
vitro.
Is there a vaccine ?
There is currently no vaccine to protect against COVID-19. the best way to
prevent infection is to take everyday preventive actions, like avoiding close
contact with people who are sick & washing your hands often.
16. Conclusion
The COVID-19 outbreak is rapidly increasing in the
number of cases, deaths and countries affected. Much is
unknown about the virus and its effects, including its
modes of transmission, the basic reproduction number,
risk factors. is highly likely that there will be addi tional
global spread of the virus.