Severe acute respiratory syndrome coronavirus 2, previously known by the provisional name 2019 novel coronavirus, is a positive-sense single-stranded RNA virus.

1. Presented by
Dr. Bratati Dey
COVID-19

2. CONTENT
⸎INTRODUCTION
⸎HISTORY
⸎DEFINITION OF CORONAVIRUS
⸎CLASSIFICATION
⸎CLINCAL FEATURES
⸎INVESTIGATION
⸎PROPHYLAXIS & MANAGEMENT
⸎CONCLUSION
⸎REFERENCES

3. “Coronavirus” Why it is Named ?
• Coronaviruses are enveloped and contain a large helical
nucleocapsid inside.
• In particular, the protruding spike protein (S) characterizes the
crown shaped virion, which it was named after.
• “Corona” (crown) refers to the characteristic appearance
of virions under electron microscopy with a fringe of large,
bulbous surface projections creating an image reminiscent of
the solar corona.

4. INTRODUCTION
⁕ Coronaviruses (family Coronaviridae) are enveloped,
spherical, and about 120 nm in diameter and possess a single
strand RNA genome of approximately 30 kb.
⁕ It is a positive strand RNA virus.
⁕ Positive-strand RNA viruses comprise of five families—
picornavirus, flavivirus, calicivirus, togavirus, and coronavirus

5. coronavirus was discovered in 2003, as a newly emerging
virus.
More recently, the MERS (Middle-East respiratory syndrome)
outbreak in the Middle East has drawn attention to human
coronaviruses again.

6. What are Hallmark of positive strand
RNA virus?
The genomic
RNA itself is
“infectious.” In
other words, a
progeny virus
is produced
when the viral
genomic RNA
is introduced
to the cell by
transfection.
The genomic
RNA itself
serves as
mRNA for the
synthesis of
viral proteins.
The viral RNA
genome
replicates via
double-strand
RNA as an
intermediate.
The virus life
cycle including
the viral
genome
replication is
confined to the
cytoplasm. The
nuclear
functions of
host cells are
largely
dispensable for
the
propagation of
positive-strand
RNA viruses.

7. CLASSIFICATION OF POSITIVE
STRAND RNA VIRUS
FAMILY GENUS SPECIES
PICORNAVIRUS Enterovirus Poliovirus
Rhinovirus Human rhinovirus
Flavivirus Flavivirus Japanese encephalitis
virus
Hepacivirus Hepatitis C virus
Calicivirus Norovirus Norovirus
Togavirus Alphavirus Semliki forest virus
Rubivirus Rubella virus
Coronavirus Coronavirus SARS-coronavirus

8. EPIDEMIOLOGY
 A novel human coronavirus, MERS-CoV, is responsible for a
new emerging respiratory infection that occurred in 2012 in
Middle East countries, including Saudi Arabia.
 WHO gave a risk assessment In 2020, china has very high risk
 Now it became a pandemic disease.

10. Situation in number by WHO
Globally 81109
confirmed (871 new)
China 78 191
confirmed (412
new) 2718 deaths
(52 new)
Outside of China
2918 confirmed
(459 new) 37
countries (4 new)
44 deaths (10
new)
Updated till: 03/03/2020

11. Genome Structure
 The genome of coronavirus represents a large single-strand
RNA of 27-32 kb.
 It is the largest RNA genome among animal RNA viruses.
 In addition to the large genomic RNA, coronaviruses have
eight subgenomic RNAs, each of them encoding one structural
protein.
 In particular, the S (spike) envelope glycoprotein binds to the
host cell receptor and determines tissue tropism and host
range.

12. Virion structure

13. “Novel Coronavirus” Why it is
Named ?
• A 1981 novel by horror writer
Dean Koontz predicted
the coronavirus outbreak, it has
been claimed.
• Acc. To UNICEF A novel
coronavirus (CoV) is a new strain
of coronavirus.

14. CLASSIFICATION
Genus Virus Species Host Disease
Alpha
Coronavirus
Human coronavirus-229E Human Colds, pneumonia
Human coronavirus-NL63 Human Colds, pneumonia
Transmissible gastroenteritis
virus (TGEV)
Swine Gastroenteritis
Beta
Coronavirus
Mouse hepatitis virus (MHV) Rodents Hepatitis
Human coronavirus-HKU1 Human Pneumonia
SARS-coronavirus (SARS-CoV) Human Pneumonia,
Gastroenteritis
MERS-coronavirus (MERS-
CoV)
Human,
camel
Respiratory
infection
Gamma
Coronavirus
Avian infectious bronchitis virus
(AIBV)
Avian Kidney infection

15. SARS-CoV
 SARS outbreak first occurred in Southern China (including
Hong Kong), and spread to South East Asia and Northern
America within a few weeks.
 It turned out that bats were the reservoir for SARS-CoV.
 ACE (angiotensin-converting enzyme 2) was identified as the
cellular receptor for virus entry of SARS-CoV to human
infection.

16. MERS-CoV
 MERS outbreak first occurred in the Middle East (mainly
Saudi Arabia) in 2012, and spread to European countries in a
limited manner.
 As of June 2015, MERS-CoV caused 1266 cases and 470
deaths reported in multiple countries.
 MERS-CoV is considerably higher than that of SARS-CoV,
approaching 30%. It is speculated that the virus spreads from
bats to human via dromedary camel.

17. MERS-CoV
 The risk of sustained person-to-person transmission appears to
be very low.
 Recently, dipeptidyl peptidase 4 (DPP4 or also known as
CD26) was identified as the cellular receptor for virus entry of
MERS-CoV.
 Further, a mouse model for MERS-CoV infection was
established that expresses the DPP4.
 It is hoped that the established mouse model will facilitate the
development of a vaccine and antiviral drugs.

18. COVID-19
⁎ COVID-19 is not SARS and it is not influenza. It is a new
virus with its own.
⁎ COVID-19 transmission in children appears to be limited.
⁎ Applied non-pharmaceutical, public health measures to
interrupt chains of human-to human transmission in a range of
settings in China.

19. COVID-19
⁕ It is unique among human coronaviruses in its combination of
high transmissibility.
⁕ It must be assumed that the global population is susceptible to
this virus.
⁕ As the animal origin of the COVID-19 virus is unknown at
present, the risk of reintroduction into previously infected
areas must be constantly considered.

20. ETIOLOGICAL FACTORS
 It is believed that bat coronavirus had acquired the ability to
infect human, extending the host range, by having a few
mutations in the spike protein.
 Pangolin are suspected as a potential coronavirus host.

21. Routes of Transmission
◘ The disease is presumed to be spread by droplets, close direct
or indirect contact, but the relative importance of these routes
of transmission is presently unclear.

22. CLINICAL FEATURES
 Respiratory infection – coughing, sneezing, shortness of breath
 Flu like symptoms
 Fever
 Severe pneumonia
 Breathing difficulty

23. INVESTIGATION
 Viral culture
 Real-time PCR (RT-PCR) assays
 RNA assays
 Antibody & antigen assays,

24. Precaution
 Use of mouth mask (N-95, PM 2.5)
 Perform hand hygiene frequently after contact with
respiratory secretion
 Not to use of packed food

25. What is the best way to wash hands properly?
(acc. To UNICEF)
Wet hands with running water
Apply enough soap to cover wet hands
Scrub all surfaces of the hands –for at least
20 seconds.
Rinse thoroughly with running water
Dry hands with a clean cloth or single-use
towel

26. Recommendation for outpatient care
⁂ Triage and early recognition;
⁂ Emphasis on hand hygiene, respiratory hygiene and medical
masks to be used by patients with respiratory symptoms;
⁂ Appropriate use of contact and droplet precautions for all
suspected cases;

27. Recommendation for outpatient care
⁂ Prioritization of care of symptomatic patients
⁂ When symptomatic patients are required to wait, ensure they
have a separate waiting area
⁂ Educate patients and families about the early recognition of
symptoms, basic precautions to be used and which health care
facility they should refer to.

28. PROPHYLAXIS
WHO officials said the first vaccine for the
coronavirus could be available in 18 months.

29. The Effects of Temperature and Relative Humidity
on the Viability of the SARS Coronavirus
 The dried virus on smooth surfaces retained its viability for
over 5 days at temperatures of 22–25◦C and relative humidity
of 40–50%, that is, typical air-conditioned environments.
 virus viability was rapidly lost (>3 log10) at higher
temperatures and higher relative humidity (e.g., 38◦C, and
relative humidity of >95%).

30. The Effects of Temperature and Relative Humidity
on the Viability of the SARS Coronavirus
 The better stability of SARS coronavirus at low temperature
and low humidity environment may facilitate its
transmission in community in subtropical area (such as Hong
Kong).
 During the spring and in air-conditioned environments.

31. Inactivation of Coronavirus
◘ Infectivity of the virus was lost after heating at 56°C for 15
minutes but that it was stable for at least 2 days following
drying on plastic.
◘ It was completely inactivated by common fixatives used in
laboratory.
◘ It was also inactivated by ultraviolet light, alkaline (pH > 12),
or acidic (pH < 3) conditions.

32. WHO’S STRATEGIC OBJECTIVES
ᴥ Limit human-to-human transmission including reducing
secondary infections among close contacts and health care
workers, preventing transmission amplification events, and
preventing further international spread from China;
ᴥ Identify, isolate and care for patients early, including
providing optimized care for infected patients;
ᴥ Identify and reduce transmission from the animal source;

33. WHO’S STRATEGIC OBJECTIVES
ᴥ Address crucial unknowns regarding clinical severity, extent of
transmission and infection, treatment options, and accelerate
the development of diagnostics, therapeutics and vaccines;
ᴥ Communicate critical risk and event information to all
communities and counter misinformation;
ᴥ Minimize social and economic impact through multisectoral
partnerships.

34. Priority research areas with immediate,
intermediate and longer-term goals
Immediate Goals Intermediate Goals Long-term goals
Diagnostics: RNA assays,
antibody & antigen assays,
point of care detection
Diagnostics: Multiplex
diagnostic platforms
Diagnostics: Prognostic
markers
Therapeutics: Remdesivir,
favipiravir, chloroquine,
plasma, TCM
Therapeutics: intravenous
immunoglobulin (IVIg)
Therapeutics: Innovative
approaches
Vaccines: Development of
animal models
Vaccines: mRNA
candidates and candidate
viral vectors
Vaccines: inactivated
candidates and subunit
candidates

35. REFERENCES
 Molecular Virology of Human Pathogenic Viruses. DOI:
http://dx.doi.org/10.1016/B978-0-12-800838-6.00013-8
 K. H. Chan et al, The Effects of Temperature and Relative Humidity on the
Viability of the SARS Coronavirus, Research Article, Received 25
November 2010; Accepted 31 July 2011, doi:10.1155/2011/734690
 World Health Organization, Coronavirus disease 2019 (COVID-19)
Situation Report – 37
 World Health Organization, Coronavirus disease 2019 (COVID-19)
Situation Report – 41
 Molecular Virology of Human Pathogenic Viruses. Chapter – 13 DOI:
http://dx.doi.org/10.1016/B978-0-12-800838-6.00013-8 © 2017
 Report of the WHO-China Joint Mission on Coronavirus Disease 2019
(COVID-19) 16-24 February 2020
 Report of the WHO-China Joint Mission on Coronavirus Disease 2019
(COVID-19)

36. THANKYOU