Severe Acute Respiratory Syndrome

SARS is a highly contagious disease that caused a worldwide pandemic in 2002 and 2003 [1] causing the death of many people [2]. The spread of the disease is especially rapid due to the extensive transportation of people and goods worldwide [3]. A high degree of suspicion, awareness, and surveillance is necessary to prevent this life -threatening illness [3]. The cause of SARS is known to be the corona virus [4]. It has an animal reservoir, usually bats, although it may also reside in camels or chimpanzees. The mode of transmission of the virus is either animal to human or most commonly, from infected humans to humans via the droplets of sneeze or a cough. The virus can also spread by direct contact i.e. by touching infected surfaces and then touching one's nose, eyes or mouth. The signs and symptoms of SARS in the initial stages resemble those of the common cold or other common respiratory illnesses but are usually more severe. There may be an initial prodrome of easy fatigability, malaise, and headache during the incubation period which can last from 2 to 10 days. Other symptoms may include high-grade fever, dyspnea, cough, and diarrhea [5]. On auscultation of the chest, inspiratory crackles may be diagnosed. In severe cases, respiratory as well as multi-organ failure will necessitate ventilator and life support measures in the intensive care unit.

Risk factors for mortality include old age, the presence of medical comorbidities, elevated lactic dehydrogenase levels and elevated neutrophil counts.

A thorough patient history and clinical suspicion are essential for early diagnosis of the illness. SARS should be suspected in a patient who has a cough, and dyspnea, especially if there is a concomitant history of contact with an infected person and/or recent air travel.

Routine laboratory tests like complete blood count, liver function tests, and creatine kinase assessment are performed and may show leukopenia, lymphopenia, elevated liver enzymes and lactic dehydrogenase and creatine kinase levels [6]. A radiograph of the chest may reveal either focal infiltrates or diffuse pulmonary infiltrates [6]. The rapid polymerase chain reaction (PCR) test, SARS antibody test and isolation of the SARS virus are recommended to identify the causative virus. However, these tests may be negative in the early phase of the illness and have their own limitations.

Other tests like enzyme-linked immunosorbent assay (ELISA) and immunofluorescent antibody tests are still under development [3]. Therefore, the diagnosis has to be based on history and clinical findings to prevent rapid progression of the disease.

1. Anderson RM, Fraser C, Ghani AC, et al. Epidemiology, transmission dynamics and control of SARS: the 2002–2003 epidemic. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences 2004;359:1091–1105.
2. Centers for Disease Control and Prevention, 2014. https://www.cdc.gov/sars/about/fs-sars.pdf. Accessed January 12,2017
3. Al-Hazmi A. Challenges presented by MERS corona virus and SARS corona virus to global health. Saudi J Bio Sci. 2016 Jul; 23(4): 507-511
4. Poon LL, Guan Y, Nicholls JM, et al. The etiology, origins, and diagnosis of severe acute respiratory syndrome. The Lancet Infectious Diseases 2004; 4: 663–671.
5. Leung CW, Chiu WK. Clinical picture, diagnosis, treatment and outcome of severe acute respiratory syndrome (SARS) in children. Paediatr. Respir. Rev. 2004;5(4):275–288.
6. Manocha S, Walley KR, Russell JA. Severe acute respiratory distress syndrome(SARS): a critical care perspective. Crit Care Med. 2003 Nov; 31(11): 2684 -92