Is SARS (Severe Acute Respiratory Syndrome) a worldwide threat?

Home/Health/Is SARS (Severe Acute Respiratory Syndrome) a worldwide threat?

Is SARS (Severe Acute Respiratory Syndrome) a worldwide threat?

Introduction

SARS or Severe Acute Respiratory Syndrome is a communicable respiratory illness, which has been recently reported in China, Hongkong, Singapore, Vietnam, Canada and many other countries. In India, some SARS cases have been reported from Goa, Pune and Delhi. The cause of SARS has recently been confirmed to be a virus belonging to the Corona virus family. The term “Corona” refers to a prominent crown like halo of spikes protruding from the envelope of the virus. Corona viruses have been known to cause respiratory infections such as common cold.

Extent of problem

According to a recent WHO report there are 5462 total cases of SARS spread along 27 countries. The number of new cases since last WHO updated is 429 (updated on 29 April 2003). The number of recovered cases is 353.  In China, Hong Kong (special administrative region) the total number of cases 1572 with 150 deaths. The maximum number of cases (cumulative) in China is 3303 with 148 deaths. As can be seen from the above report, the death rates are highest in China and Hong Kong.

Symptoms

The illness usually starts with fever (more than 100­.4­0 F) which may be associated with chills, rigors and other symptoms including headache, body ache and a general feeling of ill-being.

After about 3-7 days respiratory symptoms may supervene leading to dry, non-productive cough and difficulty in breathing. In about 10% cases the difficulty in breathing may increase further necessitating ventilator support (mechanical ventilation).

Ventilator support, presence of co-existing illnesses and age (>40 yrs.) are important prognostic indicators.

Transmission

SARS is believed to spread from one person to another by contact with exhaled droplets and bodily secretions from an infected person. This means that healthy individuals may get infected by air that has been contaminated due to sneezing or coughing by an infected person.

Case definitions

The case definitions for SARS are based on recent findings about the disease based on the latest available data and may need to be revised from time to time. SARS is currently a diagnosis of exclusion and therefore, the status of a case can change over a period of time.

Suspect case:

I.  A person presenting after 1st November 2002 with history of:

  • high fever (>38°C/ 100.4°F), with
  • cough or breathing difficulty, with
  • any or all of the following exposures (within 10 days prior to onset of symptoms):

o    close contact with a suspect or probable case of SARS

o    travel to an affected area

o    living in the affected area

II. A person with unexplained respiratory disease leading to death after 1st November 2002 in whom no autopsy has been performed and any or all of the following exposures (within 10 days prior to onset of symptoms):

  • close contact with a suspect or probable case of SARS
  • travel to an affected area
  • living in the affected area

Probable case:

I. A suspect case with X-ray evidence of infiltrates consistent with pneumonia or respiratory distress syndrome.

II. A suspect case with autopsy findings consistent with the pathology of respiratory distress syndrome with an identifiable cause.

Exclusion criteria:

A case can be excluded if an alternative diagnosis could explain the illness.

Diagnosis

Patients presenting with any of the symptoms attributable to SARS should be immediately admitted in the hospital and kept in isolation. Once the patient is admitted, the following investigations need to be carried out to help in the diagnosis of SARS:

  • Total Leucocyte Count (TLC) and Platelet Count (usually decreased in severe infection)), Creatinine Phosphokinase (elevated in early infection), Liver Function Tests (transaminase levels increased 2-6 times the normal value), Serum Electrolytes, C-Reactive Protein
  • Chest X-ray (may show generalized, patchy infiltrations in the lung fields; in late stages areas of consolidation may also be seen)
  • Arterial blood gas analysis (ABG) may show hypoxemia.
  • PCR (polymerase chain reaction) test is more definitive test for it detects the genetic material of the SARS virus in blood, stool and sputum.
  • Cell culture: Virus present in respiratory secretions, blood and stool can be grown and isolated in cell cultures. Once isolated, these can be further identified as the SARS virus.

Collection of Samples

Clinical samples to be taken for detection of SARS virus includes:

  • Nasopharyngeal Wash/Aspirate
  • Nasopharyngeal/Oropharyngeal swab (swab to be taken from the throat)
  • Bronchoalveolar Lavage, tracheal aspirates
  • Serum (Paired Sera, one from the acute and another from the convalescent phase)
  • Whole blood
  • Urine
  • Stool
  • Tissues (From Lung and upper airway)

Clinical samples to be taken from suspect case include:

  • Nasopharyngeal/Oropharyngeal swab
  • Whole blood
  • Serum

Clinical samples to be taken from probable case include:

  • Nasopharyngeal wash/Aspirate
  • Nasopharyngeal/Oropharyngeal swab
  • Bronchoalveolar Lavage, tracheal aspirates
  • Whole blood
  • Serum

Clinical samples to be taken from fatal case include:

  • Fixed tissue (All major organs)
  • Frozen tissue (Lung and upper airway)
  • Nasopharyngeal Aspirates
  • Nasopharyngeal/Oropharyngeal swab
  • Bronchoalveolar Lavage
  • Whole blood
  • Serum

It is important to note that the above mentioned samples should be collected within 72 hours of illness and transported in sterile capped unbreakable containers within 24 hours of collection. One should not collect samples in containers having cotton plugs.

Laboratories for analysis of collected samples

Samples should be sent to the following laboratories for analysis:

  • National Institute of Virology 20-A, Dr. Ambedkar Road, Pune-411001 Tel:020-6126302,6127301,6127303 E-mail:icmrniv@icmrniv.ren.nic.in
  • National Institute of Communicable Disease 22, Shamnath Marg, Delhi-110054 Tel:011-23928700,23943601,23971272 E-mail:dirnicd@bol.net.in

Certain regional laboratories could also be reached for help:

  • Tuberculosis Research Centre Mayor V.R.Ramanathan Road, Chetput, Chennai-600031
  • Enterovirus Research Centre Haffkine Institute Compound, Parel, Mumbai-400012
  • National Institute of Cholera and Enteric Diseases P-33, CIT Road, Scheme XM, Beliaghata, Kolkata-700010 Tel: 033-23500448, 23537469, 23537470 E-mail:niced@cal2.vsnl.net.in

Prevention

SARS is a contagious disease, which spreads by personal contact with an infected individual. People who are taking care of infected individuals or are in close contact with them are at higher risk of getting infected. To avoid further transmission, certain preventive measures need to be taken.

Following guidelines can prevent the spread of this disease:

  • Infected individuals should cover their mouth while sneezing or coughing.
  • Masks should be worn by infected individuals and their contacts (i.e. the people around the infected person). It is important to note that viruses are extremely small particles and therefore, capable of passing through a common cotton mask. For small viruses such as SARS virus, special mask such as N-99 mask (which blocks viruses 99% of the time) and N-95 mask (which blocks viruses 95% of the time) should be used. For maximum protection, the mask would need to be perfectly fitting the wearer. However, such special types of masks are currently in extremely short supply.
  • Use of contaminated household items by other family members should be avoided as far as possible. These items can be re-used after proper washing & disinfection.
  • Disposable gloves can be used while handling the body fluids, especially sputum or phlegm of the infected person.
  • Preferably, infected individuals should remain indoors till they get well.
  • Non-essential travel to infected areas such as China, Hong Kong, Vietnam, and Singapore should be avoided or postponed.
  • Precautions (mentioned above) should be taken for upto 10 days after the infected person has stopped experiencing the symptoms.

Management

Currently the most appropriate therapeutic management for SARS is isolation, good nursing and general supportive care. Respiratory support (ventilator support) may be required in severe cases. Antiviral drug Ribavirin with or without steroids has been used in many patients. But, its effectiveness has not been clearly proven due to absence of clinical indicators

Leave A Comment