Coronavirus Disease (COVID-19) is caused by SARS-CoV-2 virus. It spreads mainly person to person and symptoms range from mild to severe illness which can lead to death. The document discusses COVID-19's structure, symptoms, transmission, diagnosis, treatment and prevention. Key facts provided include that only those sick or caring for the sick need masks; the virus is not human-made; and older individuals and those with pre-existing conditions are more vulnerable to severe illness.

1. Coronavirus Disease
COVID-19

2. Introduction
▪ Coronaviruses are a large family of viruses.
▪ Several coronaviruses are known to cause respiratory
infections in humans ranging from the common cold
to more severe diseases such as Middle East
Respiratory Syndrome (MERS) in 2003 and Severe
Acute Respiratory Syndrome (SARS) in 2012.
▪ COVID-19 is an infectious disease caused by the most
recently discovered coronavirus. This new virus and
disease were unknown before the outbreak began in
Wuhan, China, in December 2019.
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3. Nomenclature
▪ On February 11, 2020, the WHO Director-General, Dr.
Tedros Adhanom Ghebreyesus, announced that the
disease caused by this new coronavirus was a
"COVID-19," which is the acronym of "coronavirus
disease 2019".
▪ Initially, the new virus was called 2019-nCoV.
Subsequently, the task of experts of the International
Committee on Taxonomy of Viruses (ICTV) termed it
the SARS-CoV-2 virus as it is very similar to the one
that caused the SARS outbreak.
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4. Incubation period
▪ The “incubation period” means the time between
catching the virus and beginning to have symptoms of
the disease.
▪ Most estimates of the incubation period for COVID-19
range from 1-14 days, most commonly around five
days.
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5. Structure
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6. Description
▪ Coronaviruses are positive-stranded RNA viruses
with a crown-like appearance under an electron
microscope (coronam is the Latin term for crown) due
to the presence of spike glycoproteins on the envelope.
▪ SARS-CoV-2 has round or elliptic and often
pleomorphic form, and a diameter of approximately
60–140 nm. Like other Coronaviruses, it is sensitive to
ultraviolet rays and heat.
▪ Its single-stranded RNA genome contains 29891
nucleotides, encoding for 9860 amino acids.
▪ It has 89% nucleotide identity with bat SARS-like-
CoVZXC21 and 82% with that of human SARS-CoV.
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7. Contributed by Rohan Bir Singh, MD; Made with Biorender.com
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8. Symptoms
MOST COMMON
▪ Fever
▪ Fatigue
▪ Dry Cough
MAY ALSO HAVE
▪ Aches and Pains
▪ Runny nose
▪ Sore throat
▪ Shortness of Breath
In critical cases,COVID-19 can cause severe pneumonia or a multiple-
organ failure and can lead to death
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9. Transmission
▪ The disease can spread from person to person through
small droplets from the nose or mouth of a person
with COVID-19 coughs or exhales.
▪ These droplets land on objects and surfaces around the
person.
▪ Other people then catch COVID-19 by touching these
objects or surfaces, then touching their eyes, nose or
mouth.
▪ People can also catch COVID-19 if they breathe in
droplets from a person with COVID-19 who coughs
out or exhales droplets.
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10. 10
Primary
Host
(Bats)
Intermediate
Host
(Suspected as
Pangolins)
Human Host
When the
infected
person cough
or sneeze
Droplets
containing
virus in the air
Droplets land
in the nose
mouth and
reach lungs
Droplets fall
on objects
On fingers
from touching
The droplets
eventuallly get
into nose and
mouth
Transmission
Flowchart

11. Diagnosis
▪ The WHO recommends collecting specimens from
both the upper respiratory tract (naso- and
oropharyngeal samples) and lower respiratory tract
such as expectorated sputum, endotracheal aspirate, or
Broncho alveolar lavage.
▪ In the laboratory, amplification of the genetic material
extracted from the saliva or mucus sample is through a
reverse polymerase chain reaction (RT-PCR), which
involves the synthesis of a double-stranded DNA
molecule from an RNA mold.
▪ Once the genetic material is sufficient, the search is
for those portions of the genetic code of the
coronavirus that are conserved. Presence of the
portions confirms the disease.
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12. Treatment
▪ There is no specific antiviral treatment recommended
for COVID-19, and no vaccine is currently available.
▪ The treatment is symptomatic, and oxygen therapy
represents the major treatment intervention for patients
with severe infection.
▪ Mechanical ventilation may be necessary in cases of
respiratory failure refractory to oxygen therapy,
whereas hemodynamic support is essential for
managing septic shock.
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13. Drugs under testing
▪ While studies are on, and different countries try
various combinations to treat its patients, the WHO
launched a multicountry clinical trial to test four drug
combinations that have yielded results – an
experimental antiviral drug called remdesivir, the
antimalarial drug chloroquine (or the related
hydroxychloroquine),a combination of two HIV drugs
(lopinavir/ritonavir), and those same two HIV drugs
along with the anti-inflammatory interferon beta.
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14. Prevention
▪ Avoid close contact with subjects suffering from acute
respiratory infections.
▪ Wash your hands frequently, especially after contact
with infected people or their environment.
▪ People with symptoms of acute airway infection
should keep their distance, cover coughs or sneezes
with disposable tissues or clothes and wash their
hands.
▪ Individuals who are immunocompromised should
avoid public gatherings.
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15. Importance of social distancing
▪ Social distancing includes ways to stop or slow the
spread of infectious diseases.
▪ It means less contact between you and other people.
▪ Social distancing is important because COVID-19 is
most likely to spread from person-to-person through
direct close contact with a person while they are
infectious or in the 24 hours before their symptoms
appeared.
▪ So, the more space between you and others, the harder
it is for the virus to spread.
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16. Effects in lungs
▪ The infection reach the lungs, causing inflammation in
their mucous membranes and damaging their air sacs.
The inflammation hampers the lungs’ ability to
oxygenate the blood.
▪ The inflammation in the lungs, and their reduced
efficacy, can cause them to fill with fluids, pus and
dead cells, and cause an infection, leading to
pneumonia.
▪ Some people who are infected have difficulty
breathing and require a ventilator, and for others, the
lungs become so inundated with fluids that even with
intervention, they die.
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17. Effects in other organs
▪ The virus can also enter the bloodstream, and may be
able to infect the gastrointestinal system, causing
symptoms like diarrhea and indigestion.
▪ The infection can also directly damage organs
including the heart, kidneys, and liver, and cause
bone marrow to become inflamed. Small blood vessels
may also be vulnerable to inflammation.
▪ The body’s own immune response to the infection can
cause inflammation and organ malfunction. It is still
unclear if the brain is affected.
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18. 18
Replication

19. Severity
Mild
An upper respiratory tract viral infection, including mild
fever, cough (dry), sore throat, nasal congestion,
malaise, headache, muscle pain, or malaise.
Moderate
Respiratory symptoms such as cough and shortness of
breath (or tachypnea in children) are present
without signs of severe pneumonia.
Severe
Fever is associated with severe dyspnea, respiratory
distress, tachypnea (> 30 breaths/min), and hypoxia.
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20. Stages
Stage 1 | Imported Cases: These are those who have
travelled to virus-hit foreign countries and have come
back.
Stage 2 | Local Transmission: These are those cases
who have come in contact with patients who have a
travel history.
Stage 3 | Community Transmission: Community
transmission is when a patient not exposed to any
infected person or one who has travelled to any of the
affected countries tests positive. Large areas get affected
when community transmission takes place.
Stage 4 | Epidemic: This is the last and the worst stage
where the disease take the shape of an epidemic with no
clear end point.
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21. 21
Disease Flu COVID-19 SARS MERS
Incubation time 1-4 days 4-14 days* 2-7 days 6 days
Case Fatality
Rate(CFR)
0.05-0.1% ~3.4%* 9.6-11% 34.4%
Basic
Reproductive
Number(R0)
1.3 2.0-2.5* 3 0.3-0.8
Hospitalization
Rate
2% ~19%* Most cases Most cases
Community
Attack Rate
10-20% 30-40%* 10-60% 4-13%
Disease Causing
Pathogen
Influenza virus SARS-CoV-2 SARS-CoV MERS-CoV
*COVID-19 data as of March 2020.
Comparison with other Respiratory Viral Infections

22. Facts
▪ Only wear a mask if you are ill with COVID-19
symptoms (especially coughing) or looking after
someone who may have COVID-19. If you are not ill
or looking after someone who is ill then you are
wasting a mask.
▪ The virus’s genetic makeup reveals that SARS-CoV-2
isn’t a mishmash of known viruses. Therefore, it is not
a human made virus.
▪ WHO is continually updating technical guidance for
COVID-19, including recommendations on laboratory
testing. Chest CT scan is also used in the diagnosis.
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23. Facts(cont.)
▪ COVID-19 is a pandemic disease.
Epidemic-Widespread in a particular region or Country.
Pandemic-It is a larger epidemic that covers several
countries or spread from one continent to another.
▪ From the evidence so far, the new coronavirus can be
transmitted in all climatic conditions including areas
with hot and humid weather.
▪ Viruses are considered as non-living outside the host
cell due to its inability to replicate outside the host cell
(obligate intracellular parasites).
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24. Facts(cont.)
▪ Older persons and persons with pre-existing medical
conditions (such as high blood pressure, heart disease,
lung disease, cancer or diabetes) appear to develop
serious illness more often than others.
▪ Studies suggest that coronaviruses may persist on
surfaces for a few hours or up to several days.
▪ This may vary under different conditions (e.g. type of
surface, temperature or humidity of the environment).
▪ Antibiotics do not work effectively against viruses.
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25. References
▪ https://www.who.int/health-topics/coronavirus
▪ https://www.ncbi.nlm.nih.gov/books/NBK554776/
▪ https://talk.ictvonline.org/
▪ Chan JF, Kok KH, Zhu Z, Chu H, To KK, Yuan S, Yuen KY.
Genomic characterization of the 2019 novel human-pathogenic
coronavirus isolated from a patient with atypical pneumonia after
visiting Wuhan. Emerg Microbes Infect. 2020;9(1):221-236.
▪ https://www.aljazeera.com/news/2020/03/coronavirus-
terminology-explained-covid-19-glossary-200323064432820.html
▪ https://www.theweek.in/news/health/2020/03/24/all-about-Cubas-
wonder-drug-being-pitched-against-coronavirus.html
▪ https://www.health.gov.au/sites/default/files/documents/2020/03/c
oronavirus-covid-19-information-on-social-distancing_2.pdf
▪ https://www.timesofisrael.com/how-does-the-coronavirus-enter-
the-body-and-what-makes-it-so-dangerous/
25

26. ▪ https://english.jagran.com/india/coronavirus-outbreak-india-in-
stage-2-of-covid19-transmission-a-look-at-four-stages-of-virus-
spread-10009781
▪ https://www.news10.com/news/coronavirus/comparing-
coronavirus-to-the-flu-and-other-respiratory-illnesses/
▪ https://www.sciencenews.org/article/coronavirus-covid-19-not-
human-made-lab-genetic-analysis-nature
Source for images
▪ http://ddnews.gov.in/sites/default/files/virus_1.jpg
▪ https://www.economist.com/img/b/1280/720/85/sites/default/files/
20200314_FBD001.jpg
▪ https://www.ncbi.nlm.nih.gov/books/NBK554776/figure/article-
52171.image.f5/?report=objectonly
▪ https://www.chemistryviews.org/SpringboardWebApp/userfiles/c
hem/image/2020/2020_02/CoronaVirus0.png
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27. Thank you