This document summarizes the epidemiology of SARS (Severe Acute Respiratory Syndrome). SARS is caused by a novel coronavirus and symptoms include fever and respiratory issues. It has a 2-7 day incubation period and is transmitted through respiratory droplets. Diagnosis involves PCR or serological testing. Health care workers were at high risk. While ribavirin was used to treat SARS, efficacy is still unclear. Prevention focuses on prompt identification, isolation, and hygienic measures.

1. EPIDEMIOLOGY
OF SARS
DR. MAHESWARI JAIKUMAR.
maheswarijaikumar2103@gmail.com

4. AGENT

7. SARS
• SARS is a communicable viral
disease, caused by a new strain
of coronavirus, which differs
considerably in genetic structure
from previously recognized
coronavirus.

8. • The most common symptoms in
patient progressing to SARS
include fever, malaise, chills,
headache, myalgia, dizziness,
cough, sore throat and running
nose.

9. • In some cases there is rapid
deterioration with low oxygen
saturation and acute respiratory
distress requiring ventilatory
support.
• It is capable of causing death in
as many as 10% cases.

10. • Chest X-ray findings typically
begin with a small, unilateral
patchy shadowing, and progress
over 1-2 days to become
bilateral and generalized, with
interstitial/confluent infiltration.

12. • Adult Respiratory Distress
Syndrome has been observed in
a number of patients in the end
stages.

13. INCUBATION PERIOD
2 to 7 days, commonly 3 to 5
days.

14. 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.

15. • The use of aerosol-generating
procedures (endotracheal
intubation, bronchoscopy,
nebulization treatment) in
hospitals may amplify the
transmission of SARS
coronavirus.

16. • 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)

17. • The SARS virus can survive for
hours on common surfaces
outside the human body and
upto 4 days in human waste.

18. • 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.

19. CASE DEFINITION
• In the period following an
outbreak of SARS, a notifiable
case of SARS is defined as an
individual with laboratory
confirmation infection with SARS
coronavirus (SARS-CoV)….cont

20. ……..cont
• Who either fulfils the clinical
case definition of SARS or has
worked in a laboratory handling
live SARS-CoV or storing clinical
specimens infected with SARS-
CoV.

21. CLINICAL CASE DEFINITION
• A history of fever or documented
fever AND
• One or more symptoms of lower
respiratory tract illness(cough,
difficulty in breathing, shortness
of breath) AND…cont

22. Cont…
• Radiographic evidence of lung
infiltrates consistent with
pneumonia or acute ARDS or
autopsy findings consistent with
the pathology of pneumonia or
ARDS without an identifiable
cause AND…..cont..

23. Cont…
• No alternative diagnosis fully
explaining the illness.

25. DIAGNOSIS-1
• Conventional reverse transcriptase
PCR (RT-PCR) and real time reverse
transcriptase PCR (real time RT-
PCR) assay detecting viral RNA
present in : …cont

26. Cont..
• Atleast 2 different clinical
specimens (nasopharyngeal and
stool specimens).

27. • The same clinical specimen
collected on 2 or more occasions
during the course of the illness
(sequential nasopgarygeal
aspirates)…OR…cont…

28. Cont…
• A new extract from the original
clinical sample tested positive by
2 different assays or repeat RT-
PCT or real-time RT-PCR on each
occasion of testing OR..cont…

29. Cont…
• Virus culture from any clinical
specimen.

30. DIAGNOSIS-2
• Enzyme Linked immunosorbant
assay (ELISA) and
immunofluorescent assay(IFA)…
as follows,,

31. • Negative antibody test on serum
collected during the acute phase
of illness, followed by positive
antibody test on convalescent-
phase serum tested
simultaneously OR..cont..

32. Cont…
• A fourfold or greater rise in
antibody titre against SARS-CoV
between an acute phase serum
specimen and a convalescent-
phase serum specimen (paired
sera) tested simultaneously.

33. • In the absence of known SARS-
CoV transmission to humans,
the positive predictive value of a
SARS-CoV diagnostic test is
extremely low; ….cont..

34. Cont…
• Therefore, the diagnosis should
be independently verified in one
or more WHO international SARS
reference and verification
network labs.

35. • Every single case of SARS should
be reported to WHO.

36. EPIDEMIOLOGICAL ASPECT
• Health Care Workers, especially
those involved in procedure
generating aerosols, accounted
for 21 % of all cases.

37. • Maximum virus excretion from
the respiratory tract occurs on
about day 10 of illness & then
declines.

38. • The efficiency of transmission
appears to be the greatest
following exposure to severely ill
patients or those experiencing
rapid clinical deterioration,
usually during the second week
of illness.

39. • Children are rarely affected by
SARS.
• International flights have been
associated with the transmission
of SARS from symptomatic
probable cases to passengers or
crew.

40. • WHO recommends exit
screening and other measures to
reduce opportunities for further
international spread associated
with air travel during the
epidemic period.

41. COMPLICATIONS
• As with any viral pneumonia,
pulmonary decompensation is
the most feared problem.

42. • Patients often require intubation
which may results in sequelae
such as; intensive care ..
Infection from nosocomial
pathogens, tension
pneumothorax from ventillation
at high peak pressures & non
cardiogenic pulmonary oedema.

43. TREATMENT
• Sever cases require intensive
support.
• Ribavirin, Lopinavir, Ritonavir and
systemic corticosteroids were used
to treat SARS during 2003 epidemic.
(The efficacy of these drugs remains
inconclusive) and research is
needed.

44. PROGNOSIS
• The overall mortality rate of
identified cases is about 14%.
• Mortality is age related.

45. • Poor prognostic factors include
advanced age, chronic hepatitis B,
Diabetes Mellitus, Acute Kidney
disease, low counts of CD4 and
CD8.

46. PREVENTION
• No vaccine is available.
• Therefore preventive measures
against SARS include the
following.

48. • Prompt identification of persons
with SARS, their movements and
contacts.
• Effective isolation of SARS
patients in the hospitals.

49. • Appropriate protection of
medical staff treating these
patients.
• Comprehensive identification
and isolation of suspected SARS
cases.

51. • Simple hygienic measures such
as hand washing after touching
the patients , use of well fitted
masks and introduction of
infection control measures.

53. • Exit screening of international
travellers.
• Timely and accurate reporting
and sharing of information with
other authorities and/ or
governments.

54. THANK YOU