faculty of health sciences national university of malaysia 2010/2011

GROUP 1: SYSTEMIC

ACUTE RESPIRATORY

SYNDROME

On 12 March 2003, the World Health Organization (WHO) issued a global alert on the outbreak of a new form of pneumonia-like-disease.

The illness, officially known as severe acute respiratory syndrome (SARS), is potentially fatal and highly contagious, and has spread quickly to many parts of the world in a matter of a few weeks.

The disease has been reported in many countries such as China, Hong Kong, Vietnam, Singapore, Canada, US, with a large number of infections and a significant number of deaths.

Since SARS is transmitted person-to –person, extermination of the agents of transmission would not be a plausible solution. 

i. victims who suffer from the illness display symptoms that are very much similar to those of the common flu

ii. it spreads from person-to person with ease

iii. with an incubation period of less than ten days, it acts fast-and in some cases, kills fast

Epidemiology of Severe Acute

Respiratory Syndrome (SARS)

In Malaysia, the outbreak resulted is two deaths due to the probability of SARS in Jerantut, Pahang and Penang. The victim who involved with history has ever visited China or Singapore. Table below shows the total number of cases includes those who've recovered or died. This Table shows the incidence of SARS in Malaysia since WHO records began on April to May 2003. Infection Mortality Recovered Reclassified

8 2 5 2

SARS epidemic has believe start from Guangdong, China. Hong Kong, Vietnam, Singapore and Taiwan are the most Asian country have been effect by this syndrome.

“Figure 1.Epidemic curve, Hong Kong.”

CountryCumulative number of

case(s)Number of

deathsCase fatality

ratio (%)

China   5327 349 7

Hong Kong   1755 299 17

India   3 0 0

Indonesia   2 0 0

Kuwait   1 0 0

Macao   1 0 0

MALAYSIA*   5 2 40

Mongolia   9 0 0

Philippines   14 2 14

Republic of Korea  

3 0 0

Singapore   238 33 14

Taiwan   346 37 11

Thailand   9 2 22

Vietnam   63 5 8Table 2 .The official number of SARS cases reported from Asian

countries over the time period November 1, 2002 to July 31, 2003

WORLDWIDE.

Table 3 .The official number of SARS cases reported from countries over the time period November 1, 2002 to July 31, 2003

CountryCumulative number

of case(s)Number of

deathsCase fatality

ratio (%)

Australia   6 0 0

Canada   251 43 17

France   7 1 14

Germany   9 0 0

Italy   4 0 0

New Zealand   1 0 0

Republic of Ireland  

1 0 0

Romania   1 0 0

Russian Federation  

1 0 0

South Africa   1 1 100

Spain   1 0 0

Sweden   5 0 0

Switzerland   1 0 0

United Kingdom  

4 0 0

United States   29 0 9

Total   8098 774 9.6

SIGN AND SYMPTOM

Signs and symptoms of SARS disease typically develop within two to 10 days after exposure to the virus.

SARS typically begins with flu-like signs and symptoms ; fever, chills, muscle aches and occasionally diarrhea. After about a week, signs and symptoms include: -Fever of 100.4 F (38 C) or higher -Dry cough -Shortness of breath

Insufficient oxygen in blood Abnormalities are noted on chest X-ray. Loss of appetite Rash Acute respiratory distress syndrome Other less common symptoms.

For PCR testing, there are at least 2 different clinical specimens needed (eg:nasopharyngeal and stool.) Besides that, there can also be the same clinical specimen collected on 2 or more days during the course of the illness for example 2 or more nasopharyngeal aspirates are obtained for diagnosis

The peak detection rate for SARS-associated coronavirus depends on the type of the specimen obtained. week 2after illness onset for respiratory specimens weeks 2 to 3 for stool or rectal swab specimens week 4 for urine specimens.

If a positive PCR result has been obtained, it should be confirmed by repeating the PCR using the original sample or having the same sample tested in a second laboratory. Amplifying a second genome region could further increase test specificity.

ELISA or IFA is a negative antibody test on acute serum followed by positive antibody test on convalescent serum.

Antibodies against SARS-CoV become detectable with high sensitivity around 10 days after the onset of infection, but they can be undetectable prior to this by current testing methods.

Positive antibody test results indicate that there has been an infection with SARS-CoV.

Seroconversion from negative to positive, or a four-fold rise in antibody titre in the serum of a convalescent patient compared with that patient’s serum during acute illness, denotes a recent infection.

A negative serological result 21 days after onset of symptoms indicates absence of SARS-CoV infection. Cross-reactions with antibodies to other agents (including the human coronaviruses HCoV-229E and HCoV-OC43) are not known.

 Antibody determination using IFA or ELISA was the most reliable method for identifying infections with SARS-CoV.

  Patient specimens such as respiratory secretions, blood, or

stool can be inoculated in suitable cell lines for growth of the infectious agent.

Vero cells have been used for culture. After isolation, the virus has to be confirmed and this is usually done with nucleic acid based tests.

Positive results indicate presence of viable SARS-CoV, whilst negative cell culture results do not exclude SARS.

These viruses were originally isolated in organ cultures of human embryonic trachea and subsequently grown in tissue culture in fibroblasts.

 Although most coronaviruses are highly species specific,able to employ a larger variety of receptors on the cell surface,show a marked degree of tissue tropism influenced by both host cell surface characteristics and by viral S-glycoprotein

At the onset of fever, 70-80 % of the patients have abnormal chest radiographs

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 or confluent infiltrates. Air-space opacities eventually develop during the course of the disease. In patients who deteriorate clinically, the air-space opacities may increase in size, extent, and severity

The initial radiographic changes may be indistinguishable from those associated with other causes of bronchopneumonia.

ANTIVIRAL THERAPY

SARS Task Force, which was formed on 15 March 2003 and chaired by the Director of medical service(DMS)

the key strategy was to detect persons with suspected or probable SARS as early as possible and isolate them in

Early identification of SARS cases was done through several ways: active contact tracing for all contacts within 24

hours of notification of a case mandatory home quarantine enforced through

the use of electronic cameras intensive education of healthcare professionals

and the public.

Preventive measure to minimise the imported cases: Health alert notices were issued at the airport

to inbound air passengers from SARS-affected countries through temperature checks using thermal imaging scanners.

Travellers picked up by the scanners had their temperature re-checked by nurses who would refer them for further examination by doctors at the air and sea terminals if they were confirmed to have a fever.

Suspected person were sent to hospital for further assessment and treatment if necessary.

All visitors through air, sea and land checkpoints were required to complete a SARS health declaration card to facilitate contact tracing.