Diseases and conditions
Severe Acute Respiratory Syndrome (SARS)

Severe Acute Respiratory Syndrome (SARS)

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SARS is a term used to describe a new, serious, contagious, respiratory illness that is often severe. SARS has been reported in Asia, North America, and Europe.  The term is applied when someone has developed SARS symptoms and has either traveled to an area of the world where it has been confirmed that SARS is spreading in the community or has had contact with an ill traveler who had been to one of the affected areas.  A virus is suspected to be the cause of SARS.  SARS appears to spread from person to person during close contact with infected persons.

Acute respiratory syndrome


SARS is caused by a corona virus, called SARS-corona virus (SARS-CoV) similar on electron microscopy to animal corona viruses. Corona viruses are large, enveloped ribonucleic acid (RNA) viruses named after their corona- or crown-like surface projections observed on electron microscopy

 Epidemiology


SARS is essentially an acute community-acquired or nosocomial pneumonia that does not respond to conventional antimicrobial therapy for known pneumonia pathogens. As of mid-2003, 8096 cases with 774 deaths occurred on five continents (World Health Organization, 2003). Interpersonal transmission has occurred in health care facilities, workplaces, homes, and public transports (World Health Organization, 2003). From September 2003 to May 2004, three laboratory-associated outbreaks were reported (Lim et al., 2004; Orellana, 2004). The laboratory acquired cases in Singapore and Taiwan were each limited to one affected person, whereas that in Beijing was associated with secondary and tertiary cases (World Health Organization, 2004).


SARS-coronavirus (SARS-CoV) is most likely zoonotic in origin and then transmitted to humans. The virus may have been circulating among wild game animals in the wet markets of southern China. The palm civet is now considered to be the most likely amplification host and one of the likely candidates for introduction to humans (Guan et al., 2003). Prevalence of about 80% was recently reported for civets in animal markets in Guangzhou (Tu et al., 2004). The initial human cases of the 2003 pandemic and those of the 2004 Guangdong outbreak were epidemiologically linked to game animals either because of occupational contact or eating (Zhong et al., 2003).


The most important route of interpersonal spread appears to be direct or indirect contact of the mucosae with infectious respiratory droplets or fomites (World Health Organization, 2003). SARS-CoV has been detected in respiratory secretions, feces, urine, and tears (Chan etal., 2004; Loon etal., 2004). Nosocomial transmission of SARS could be facilitated by the use of nebulizers, suction, intubation, bronchoscopy, or cardiopulmonary resuscitation on SARS patients by generation of large numbers of infectious droplets (Lee et al., 2003; Varia et al., 2003; World Health Organization 2003; Christian et al., 2004). Almost half of the SARS cases in Hong Kong acquired the infection within health care facilities and institutions (Leung etal., 2004). 

How SARS spreads ?


The main way that SARS seems to spread is by close person-to-person contact.  The virus that causes SARS is thought to be transmitted most readily by respiratory droplets (droplet spread) produced when an infected person coughs or sneezes.  Droplet spread can happen when droplets from the cough or sneeze of an infected person are propelled a short distance (generally up to 3 feet) through the air and deposited on the mucous membranes of the mouth, nose, or eyes of persons who are nearby.  The virus also can spread when a person touches a surface or object contaminated with infectious droplets and then touches his or her mouth, nose, or eye(s).  In addition, it is possible that the SARS virus might spread more broadly through the air (airborne spread) or by other ways that are not now known. 


Reservoir


The Himalayan masked palm civet (Paguma Larvata) is considered the main source of animal-to-human transmission of SARS-CoV. Cave-dwelling Chinese horseshoe bats are a reservoir of SARS-like c oronaviruses that are closely related to those responsible for the SARS epidemic. Data suggest SARS-CoV evolved from a natural reservoir of SARS-CoV-like viruses in horseshoe bats through civets or intermediate animal hosts in wet markets of China.
 

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Incubation Period


2-10 days (mean 5-6 days), with isolated reports of longer incubation periods


What does “close contact” mean? 


In the context of SARS, close contact means having cared for or lived with someone with SARS or having direct contact with respiratory secretions or body fluids of a patient with SARS. Examples of close contact include kissing or hugging, sharing eating or drinking utensils, talking to someone within 3 feet, and touching someone directly.  Close contact does not include activities like walking by a person or briefly sitting across a waiting room or office. 


Clinical Presentation 


Early signs and symptoms of SARS are nonspecific and consistent with influenza-like illness. Most common initial symptoms include a fever greater than 38°C (100.4°F), often accompanied by myalgia, malaise, chills, a non-productive cough, and rigor. After 2 to 7 days, this is followed by respiratory symptoms such as a dry cough, shortness of breath, difficulty breathing or hypoxia. In some cases, the respiratory symptoms become increasingly severe, and patients require oxygen support and mechanical ventilation. 


Similar to other cases of atypical pneumonia, physical signs upon chest examination are minimal compared with radiological findings, which typically show ground-glass opacities and focal consolidations. Diarrhea is the most common extra-pulmonary manifestation.
 Cases can become severe quickly, progressing to respiratory distress coinciding with peak viraemia that occurs during the second week of illness (e.g., 10 days). Nearly all confirmed infected adult cases developed pneumonia or acute respiratory distress syndrome


Diagnosis


Serology and virology tests confirm SARS and include polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assay (IFA); clinical specimens include clotted blood or serum for serology, nasopharyngeal swab (NPS) or NP aspirate, bronchoalveolar lavage (BAL)/bronchial washings and stools for viral RNA detection. Clinical presentation and epidemiological evidence supports the diagnosis.
 

Prevention


Since there is no SARS vaccine, the most effective measure to prevent SARS is to prevent transmission from infected persons to susceptible persons. All individuals presenting to a health care facility with symptoms of an acute respiratory infection (ARI) should receive information about, and the importance of, respiratory etiquette and hand hygiene; and ensure early recognition and prevention of transmission of SARS-CoV and other respiratory viruses at the initial encounter with a health care facility using the assessment protocol including travel history found in Annex B of PIDAC’s Routine Practices and Additional Practices, Prevention of 

Transmission of Acute Respiratory Infection.


1. Maintain good personal hygiene. Cover your nose and mouth when sneezing or coughing.
2. Keep your hands clean. Wash hands when they come in contact with all body fluids including respiratory secretions.
3. Avoid touching the eyes, nose and mouth. When you must touch your eyes, nose, and mouth, wash your hands first.
4. Stay away from others if you develop respiratory symptoms.
5. Do not share items such as cigarettes, towels, lipstick, toys, or other items that are likely to be contaminated with respiratory secretions.
6. Clean up surfaces contaminated with body fluids promptly with a good disinfectant solution. Follow the manufacturers’ instructions when using any disinfectant, and wear gloves.
7. Do not share food or drink with others.
8. Use serving utensils at meal times.
9. Use dishwashers and washing machines to clean dishes or clothes that are usually washed by hand.  They will provide a higher level of cleaning than if you clean these items by hand
10. Make sure that bathrooms are always stocked with soap and disposable paper towels or hand dryers.
11. Promptly dispose of used tissue paper in a waste receptacle.
12. Provide good air ventilation to indoor spaces. Consider opening a window to let in extra air.
13. Take care of yourself to improve your immune system defenses.  Eat a balanced diet, and get adequate rest.  Avoid smoking.
14. Consult your doctor promptly if you develop respiratory symptoms, and follow instructions given by your doctor including the use of drugs as prescribed and adequate rest as appropriate.

Management of Cases 


In addition to the requirements set out in the Requirement #2 of the “Management of Infectious Diseases – Sporadic Cases” and “Investigation and Management of Infectious Diseases Outbreaks” sections of the Infectious Diseases Protocol, 2018 (or as current), the board of health shall investigate cases to determine the source of infection.
Cases should not go to work, school, or other public areas until 10 days after fever and respiratory symptoms have resolved. During this time, infection prevention and control precautions for SARS patients should be followed.

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