Severe Acute Respiratory Syndrome (SARS) (cont.)

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What causes SARS? How is SARS transmitted?

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SARS is caused by a virus referred to as "SARS-CoV" from the coronavirus genus; SARS-CoV means severe acute respiratory syndrome-associated coronavirus. Many coronaviruses infect animals and humans, and the common cold is caused by some coronaviruses and several other viruses. However, the SARS-CoV virus had never been identified before 2002. This was not entirely surprising because there are many types of coronaviruses, and they are known to mutate easily.

Although scientists are not certain, it has been suggested that the SARS virus originated in wild bats and then spread to palm civets or similar mammals. The virus then mutated and adapted itself in these animals until it eventually infected humans. There was ample opportunity for the virus to come into contact with humans. Bats serve as a food source in parts of Asia, and their feces are sometimes used in folk medicines. Civets are cat-like mammals that live in the tropics of Africa and Asia and produce musk from their scent glands, which is used in perfumes. Civets are also hunted for meat in some parts of the world. These animals could easily transmit the virus to humans.

SARS-CoV is spread from person to person through respiratory secretions. SARS often affected people caring for a sick individual and spread readily through health-care facilities until infection-control measures were established. SARS-CoV was isolated from many hospital surface areas, including elevator buttons, likely contributing to the spread of the disease among healthcare workers. During the outbreak, one in about every 20 infected people was a health-care worker who cared for a patient with SARS; nearly 2,000 health-care workers became ill.

What are risk factors for SARS?

SARS-CoV can infect a person regardless of their health status or age group. However, it was clear that some people were at increased risk during the 2002-2003 outbreak. This included people over the age of 50 (some reported mortality rates of about 50%), pregnant women, and those with underlying diabetes, heart disease, or liver disease. A major risk factor is simply a close association with any person infected with SARS-CoV since the virus can be spread through droplets sprayed into the air by coughing, sneezing, or even talking.

Other risk factors include the following:

  • Recent travel to mainland China, Hong Kong, or Taiwan or close contact with ill people with a history of recent travel to these areas
  • Employment in an occupation at risk for SARS-CoV exposure, including a health-care worker with direct contact with a patient having SARS-CoV, or a worker in a laboratory that contains live SARS-CoV
  • Relationship with a cluster of cases of atypical pneumonia without an alternative diagnosis
Medically Reviewed by a Doctor on 6/25/2015

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