What is SARS-CoV (Severe Acute Respiratory Syndrome Coronavirus)?

SARS-CoV: A Highly Infectious Coronavirus with Significant Mortality Risk

SARS-CoV (Severe Acute Respiratory Syndrome Coronavirus) is a novel coronavirus that emerged in 2003 as a highly infectious respiratory pathogen with significant in-hospital mortality and considerable occupational risk for healthcare workers, causing severe respiratory illness requiring hospitalization. 1

Viral Characteristics and Classification

• SARS-CoV belongs to the Coronaviridae family, which are enveloped positive-sense single-stranded RNA viruses in the order Nidovirales 2
• It is classified as a Betacoronavirus, the same genus that includes MERS-CoV and the more recent SARS-CoV-2 3
• SARS-CoV has a large genome (approximately 30 thousand nucleotides) with 14 functional open reading frames (ORFs) 4
• The virus contains 4 structural proteins (spike, membrane, nucleocapsid, and envelope) and 8 accessory proteins that play important roles in pathogenesis 4

Mechanism of Infection and Transmission

• SARS-CoV primarily spreads through respiratory droplets and aerosols generated when infected individuals cough, sneeze, or speak 1
• The virus can remain viable on surfaces (fomites), creating additional transmission routes 1
• SARS-CoV enters human cells by binding to specific receptors, similar to how SARS-CoV-2 uses ACE2 receptors 3
• Healthcare workers are particularly vulnerable to infection when managing cases 1

Clinical Manifestations

• SARS presents as a respiratory illness characterized by: 1
  • Fever exceeding 38°C
  • Cough or breathing difficulty
  • Radiographic evidence of infiltrates consistent with pneumonia or respiratory distress syndrome (RDS)
• Approximately 23-32% of patients with SARS become critically ill 1
• Acute lung injury (ALI) is the most common severe organ dysfunction, occurring in approximately 16% of all SARS patients and 80% of critically ill SARS patients 1
• A cytokine storm has been observed in patients who develop fatal complications 1

Diagnosis

• Diagnosis cannot be established by clinical findings alone; epidemiological factors play a critical role 5
• Key epidemiological considerations include: 1, 5
  • History of travel to affected areas
  • Close contact with other case patients
  • Linkage to clusters of unexplained pneumonia
• Laboratory confirmation through viral detection is essential 5

Treatment and Management

• Management primarily involves supportive care, particularly ventilatory support 1
• Strict infection control procedures, including droplet and airborne precautions, are critical for preventing transmission 5
• The initial SARS outbreak ended in July 2003 when the World Health Organization (WHO) announced that all known person-to-person transmission had ceased 1

Public Health Significance

• The 2003 SARS outbreak affected multiple countries across Asia, North America, and Europe 1
• Between November 2002 and August 2003,8,098 people in 29 countries developed probable SARS 1
• The disease posed significant challenges to healthcare systems globally 1
• Though currently not circulating in human populations, SARS-CoV continues to represent a potential threat as it may exist in animal reservoirs 4

Distinction from SARS-CoV-2

• SARS-CoV is distinct from but related to SARS-CoV-2, which emerged in 2019 and causes COVID-19 3
• SARS-CoV-2 shares approximately 76.9% genetic homology with the original SARS-CoV virus 3
• Both viruses cause similar respiratory syndromes but with different epidemiological patterns and case fatality rates 3

Prevention

• Key preventive measures include: 5
  • Early identification and isolation of suspected cases
  • Implementation of appropriate infection control procedures
  • Contact tracing of exposed individuals
  • Use of personal protective equipment by healthcare workers