The SARS outbreak began in China in late 2002 and spread to 29 countries, infecting over 8,000 people and killing 800. SARS is caused by a novel coronavirus, which was identified in 2003. It is transmitted through respiratory droplets and contact with contaminated surfaces. Common symptoms are fever, cough and difficulty breathing. Healthcare workers were particularly at risk due to exposure to aerosol-generating procedures. International air travel helped spread SARS rapidly worldwide.

1. SARS - EPIDEMIOLOGY

2. • SARS : severe acute respiratory syndrome.
• The agent appears to be a new virus distinct from
other corona viruses which had been classified
into types1 & 2( mammalian viruses);type 3(avian
viruses).
• New SARS virus becomes corona virus type 4
& confirmed by vero cell culture , animal
inoculation, cloning , sequencing and histology.
• Corona viruses are a group of spherical or
pleomorphic ; enveloped viruses.
• Their genome is unsegmented single stranded
positive sense RNA.
• Nucleo capsid is helical.

3. • Envelope contains large
widely spaced club or
petal shaped spikes.
• They replicate in cytoplasm.
• It is difficult to grow them
in cell culture.
• They belong to family
coronaviridae and genus betacoronovirus.
• It may be a recombinant of some animal and
human corona viruses.

4. • The outbreak of sars erupted in southern china in
late 2002 and by the time it waned in mid 2003
had resulted in 8000 cases in 29 countries with
over 800 deaths.( case fatality is approximately
10%)
• In almost all cases, there was a history of close
contact with a SARS patient or of recent travel to
an area where SARS was reported. International
air travel allowed SARS to spread around the
world with unprecedented speed. The experience
with SARS illustrated that in a globalized world,
an infectious disease outbreak anywhere places
every country at risk.

5. MODE OF TRANSMISSION:
• The primary mode of transmission appears
to be through direct or indirect contact of
mucous membranes of eyes, nose, or mouth
with respiratory droplets or fomites.
• The use of aerosol-generating procedures
(endotracheal intubation, bronchoscopy,
nebulization treatment) in hospitals may
amplify the transmission of SARS coronavirus

6. • The virus is shed in stools but the role of faecal-
oral transmission is unknown
• The natural reservoir appears to be the
horseshoe bat (which eats and drops fruits
ingested by civets, the earlier presumed
reservoir and a likely amplifying host)
• The SARS virus can survive for hours on common
surfaces outside the human body and upto 4
days in human waste
• The virus can survive at least for 24 hours on a
plastic surface at room temperature and can live
for extended periods in the cold.

7. • Interestingly, a few persons with SARS were
identified as “super spreaders”; each
appeared to have infected more than 10
contacts.
• Incubation period ranges from 2 to 10 days.

9. SARS: Timeline of an Outbreak
Nov. 16, 2002 --
The first case of
an atypical
pneumonia in
the Guangdong
province in
China.
February 14, 03 : 305 cases & 5 deaths
from an unknown acute respiratory
syndrome

10. • Feb 28, 2003 -- World Health Organization
officer Carlo Urbani, MD, examined an
American businessman with an unknown
form of pneumonia in a French hospital in
Hanoi, Vietnam

11. March 03:
New reports of outbreaks came in from Hong
Kong, Singapore & Vietnam.
New syndrome was
designated as
severe acute
respiratory syndrome
or SARS

12. • March 10, 2003 -- Urbani reported an
unusual outbreak of the illness, which he
called sudden acute respiratory syndrome or
SARS, to the main office of the WHO. He also
noted that the disease has infected an
usually high number of healthcare workers
(22) at the hospital.
March 11, 2003 -- Outbreak of a mysterious
respiratory disease is reported among
healthcare workers in Hong Kong

13. • March 12, 2003 -- WHO issued a global alert
about a new infectious disease of unknown
origin In both Vietnam and Hong Kong .
• March 24, 2003 -- CDC officials present the
first evidence that a new strain of a virus
most frequently associated with upper
respiratory infections and the common cold
in humans called The corona virus might be
likely cause of SARS.
• March 29, 2003 -- Carlo Urbani, who
identified the first cases of SARS, died as a
result of the disease.

14. • April 9, 2003 -- WHO investigative team gave
initial report on Guangdong outbreak. The team
found evidence of "super spreaders“ who were
capable of infecting as many of 100 persons.
• April 16, 2003 -- A new form of a corona virus
never before seen in humans is confirmed as the
cause of SARS according to Koch's postulates,
which are four specific conditions that must be
met for a pathogen to be confirmed as a causal
agent of disease.

15. • April 20-25, 03:
Outbreaks in Hanoi, Hong Kong, China,
Singapore &Toronto showed signs of
peaking.
• April 25, 03:
Nearly 3000 SARS cases have been
identified in China.

16. • Internationally, more than 8,098 people
became ill with severe acute respiratory
syndrome. The World Health Organization
(WHO) stated a total of 774 people died
because of the SARS 2003 outbreak.
According to the CDC, the illness spread to
more than two dozen countries in North
America, South America, Europe, and Asia
before the SARS global outbreak of 2003 was
contained

18. • Health care workers especially those
involved in generating aerosols accounted
for 21% of all cases.
• Children are rarely affected by SARS .to date
, there have been 2 reported cases of
transmission from children to adults and no
report of transmission from child to child .
• 3 separate epidemiological investigations
have not found any evidence of SARS
transmission in schools.

19. • No evidence of SARS has been found infants
of mothers who were infected with pregnancy.
• International flights have been associated with
the transmission of SARS from symptomatic
probable cases to passengers or crew.
• WHO recommends exit screening and other
measures to reduce opportunities for further
international spread of the disease during
epidemics.

20. INFECTIOUSNESS OF SARS
• Factors affecting infectiousness are
– Viral load of the secretion from index patient
– Aerosol-generation procedures
– Distance of the index patient

21. WHO case definitions of SARS
• SUSPECTED CASE
A person presenting after 1st nov 2002 with
High fever
Cough or breathing difficulty
H/o contact with a probable case of SARS 10
days prior.

22. • PROBABLE CASE
• A suspect case of SARS having
X-ray findings of pneumonia
Autopsy findings consistent of RDS without
an identifiable cause
Positive for SARS corona Virus by one or
more of the assays in a lab using appropriate
quality control procedure

23. references
• Textbook of microbiology –ananthanarayan &
panikar
• Lange medical microbiology
• K park community medicine
• Wikipedia SARS.