The document discusses SARS, MERS, and COVID-19. It describes the viruses' morphology, transmission, clinical manifestations, diagnosis, treatment and prevention. SARS was identified in 2003 in China and spread to 29 countries. MERS was first reported in 2012 in Saudi Arabia. COVID-19 spreads via droplets and contact. Symptoms range from fever and cough to difficulty breathing. Diagnosis involves antigen detection, antibody testing, cell culture and RT-PCR. There are no specific treatments, but prevention includes isolation, handwashing and travel restrictions. Vaccines are currently under trial.

1. SARS
Dr Rachna Tewari
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2. SARS (Severe Acute Respiratory Syndrome)
Cause
SARS virus.
Virus identified in 2003 in China.
Coronavirus .
SARS-CoV.
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4. Morphology
Enveloped .
Carrying petal or club shaped or crown like
peplomer spikes giving appearance of solar
corona.
They are large (120-160 nm) spherical viruses
having a helical symmetry.
They possess linear, positive-sense ssRNA of 26
to 32 kbp size, largest among the non-segmemed
RNA viruses.
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6. SAR S-Co V (severe acute respiratory
syndrome corona virus)
History:
SARS was first recognized in China in 2003
by WHO physician Dr. Carlo Urbani.
He diagnosed it in a businessman who had
traveled from China to Vietnam.
The businessman and the doctor who first
diagnosed SARS both died from the illness .
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7. Epidemiology:
• During 2003 outbreak, the SARS virus
spread from Asia to various regions of the
world causing nearly 8098 cases in 29
countries, with over 774 deaths.
However, India remained free from the
infection. Since 2004, no case has been
reported from anywhere in the world .
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8. Source:
Zoonotic origin .
Horseshoe bats - its natural reservoir.
Beginning -animal-to-human later
adapted to human-to-human
transmission.
Palm civets , other mammals served as
amplification hosts.
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10. Transmission
SARS-CoV can also spread via
droplets and rarely spread through
the air (airborne spread).
Human coronaviruses spread by
coughing, sneezing, and close
personal contact, such as touching
mouth, nose, or eyes or shaking
hands.
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11. Clinical manifestation
Severe lower respiratory tract infection .
Characterized by muscle pain .
Headache, sore throat and fever.
Followed by the onset of respiratory symptoms
Cough
Dyspnoea
Severe pneumonia
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12. MERS CoV
• Middle East Respiratory Syndrome Coronavirus
• Caused - severe form of lower respiratory illness .
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13. Epidemiology:
First reported in Saudi Arabia in 2012.
Saudi Arabia, UAE, Qatar, Oman.
Kuwait, Yemen, Lebanon and Iran.
It is not reported from India yet.
Mortality of 30%.
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14. Source
• Acquired from camels and bats.
People at increased risk for MERS-CoV
infection include:
• Recent history of travel from the
Arabian Peninsula within 14 days
• People with exposure to infected
camels.
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15. Transmission
• Close contacts of a confirmed case of MER$.
• Healthcare personnel.
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16. Clinical manifestation
• Incubation period 2- 14 days.
• Severe acute respiratory symptoms
fever, cough and shortness of breath.
• Gastro intestinal symptoms
diarrhea and nausea/ vomiting.
• Complications
pneumonia and kidney failure occur, especially in people with underlying
comorbid conditions.
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17. SARS COV- 2
Morphology
Spherical
Enveloped
Helical symmetry.
+ SS RNA .
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18. Structure
• Outer – envelope
• Matrix layer .
• Nucleocapsid.
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19. Nucleocapsid
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20. Antigens
• Envelop E .
• Matrix protein M.
• Spike glycoproteins S .
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21. Source and transmission
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22. Transmission
• Droplet infection.
• Contact .
• Airborne .
• Conjunctiva .
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24. Pathogenesis
• Spike receptors bind to ACE - 2 receptors
on host cell.
Virus enters the host cell.
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25. Replication
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27. Cell death occurs
• The new coronavirus can also
push the immune system into
overdrive, unleashing an
indiscriminate assault -- known as
a cytokine storm -- on pathogens
and their human hosts alike.
Most viruses can cause disease in
two ways –
They can damage tissue where the
virus replicates, or they can cause
damage as a side-effect of the
immune system fighting off the
disease."
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28. Clinical features
Most common symptoms:
• fever
• dry cough
• tiredness
Less common symptoms:
• aches and pains
• sore throat
• diarrhoea
• conjunctivitis
• headache
• loss of taste or smell
• a rash on skin, or discolouration of fingers or toes
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29. Serious symptoms:
• Difficulty breathing or shortness of breath
• Chest pain or pressure
• Loss of speech or movement
• Catalogue of syndromes affecting almost
all the body's organs, from the brain to the kidneys.
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31. Lab Diagnosis
• Sample -
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32. Laboratory Diagnosis
Antigen detection:
Coronavirus antigens in the
respiratory epithelial cells may be
detected by ELISA using specific
monoclonal antibody.
Electron microscopy can be used
to detect enteric coronaviruses
from stool.
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33. Serum antibody detection
• ELISA and hemagglutination
inhibition test are available.
• Rising titer of antibody between
acute and convalescent sera can
be used to establish the diagnosis.
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34. cell culture
Isolation of human coronaviruses
in cell culture has been extremely
difficult.
Traditional tracheal ring culture is
no longer in use.
SARS-CoV was isolated from
respiratory specimens using Vero
cell line.
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35. RT PCR
• RT-PCR assays are useful to
detect coronavirus RNA in
respiratory secretions and in
stool samples and SARS-CoV
RNA from blood.
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36. Treatment and Prevention
There are no specific drugs or vaccine available for
coronavirus infections.
Control measures include:
• Isolation of patients
• Quarantine of exposed people
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37. Prevention
Travel restrictions
Use of gloves, gowns, goggles and
respirators by healthcare workers
Hand washing
Avoiding personal contact
Avoiding contact with camels .
Taking effective control measures
was the main reason behind
preventing SARS transmission in
2003.
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38. TREATMENT
• HYDROXYCHLOROQUINE
• REMDISIVIR
• IVERMECTIN
• AZITHROMYCIN
• PARACETAMOL
• VENTILATOR
• CONVALESCENT PLASMA.
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39. Vaccines
• Under trial .
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40. Questions ???
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