Disease: Severe Acute Respiratory Syndrome (SARS)

    Severe acute respiratory syndrome (SARS) facts

    • SARS is febrile severe acute respiratory syndrome that first appeared in 2003 and spread rapidly to more than two dozen countries across the world, infecting over 8,000 people and killing 774 before it could be contained in 2004.
    • SARS is caused by a coronavirus (SARS-associated coronavirus or SARS-CoV) that exists in bats and palm civets in Southern China.
    • This infection can be spread easily from close person-to-person contact (such as living in the same household) via respiratory droplets that come in contact with skin or mucous membranes (eyes, mouth, or nose).
    • Infected people become ill within a week of exposure. During the first week, nonspecific symptoms of a flu-like illness begin. This period is followed by a syndrome of "atypical" pneumonia, including dry cough, and progressively worsening shortness of breath with poor oxygenation. Severely affected people experience respiratory failure and may need mechanical ventilation.
    • Since these are nonspecific symptoms and findings, the diagnosis of SARS is only considered if the individual has also had specific risk factors within 10 days prior to illness.
    • If there are grounds for suspicion, respiratory secretions are sent for testing at the CDC.
    • There is no medication that is known to treat SARS. Treatment is supportive.
    • During the 2003 outbreak, approximately 25% of people had severe respiratory failure and 10% died.
    • The SARS outbreak in 2002-2003 was controlled solely by using public-health measures, such as wearing surgical masks, washing hands well, and isolating infected patients.

    What is severe acute respiratory syndrome (SARS)?

    SARS is an infectious respiratory illness caused by a coronavirus. The first cases of SARS occurred in late 2002 in the Guangdong Province of the People's Republic of China. Because of the contagious nature of the disease and the delayed public-health response, the epidemic spread rapidly around the globe. Final statistics from the World Health Organization showed 8,096 reported illnesses and 774 deaths.

    The rapid transmission and high mortality rate (about 10%) of SARS drew international attention and concern. Fortunately, efforts to identify and quarantine infected people proved highly effective. By July 2003, sustained human-to-human transmission of SARS had been eliminated. This was a public-health triumph that is often under-appreciated. Although illnesses such as anthrax or bird flu are potential threats, SARS was a very real problem. Unfortunately, future outbreaks of SARS are still possible because the virus lives in some wild bats and civets in China and also exists in laboratory cultures. In fact, there were a few human cases of SARS in 2004 as a result of laboratory accidents in the People's Republic of China. No human cases have been identified since.

    The previously unknown coronavirus that causes this syndrome was first identified in Asia in early 2003, hence its name, "SARS-associated coronavirus" or SARS-CoV. As of October 2012, SARS-CoV has been added to the National Select Agent Registry, which regulates the handling and possession of bacteria, viruses, or toxins that have potential to pose a severe threat to public health and safety. The addition of SARS-CoV permits maintenance of a national database and inspection of entities that possess, use, or transfer SARS-CoV; it also ensures that all individuals who work with these agents undergo security-risk assessment performed by the Federal Bureau of Investigation/Criminal Justice Information Service.

    Middle East respiratory syndrome coronavirus (MERS-CoV) is a new coronavirus in humans that has been identified in an outbreak in residents and travelers to the Arabian peninsula in 2012. It is not the same coronavirus as SARS-CoV, but it is similar to bat coronaviruses, and it is likely to have originated in animals as well. MERS-CoV is discussed separately in another article.

    What causes SARS? How is SARS transmitted?

    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. 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

    What are SARS symptoms and signs?

    Symptoms begin two to seven days after acquiring the virus. Initially, the illness resembles influenza and lasts for up to one week. Symptoms include fever, chills, headache, muscle aches, and poor appetite; nausea, vomiting and diarrhea are less common. This period is followed by a syndrome suggesting atypical pneumonia, including dry cough and progressively worsening to severe shortness of breath (dyspnea) and inability to maintain oxygenation (hypoxia). Progression may be rapid or it may take several days. Severely affected people develop a potentially fatal form of respiratory failure, known as adult respiratory distress syndrome (ARD or ARDS). In addition to the attacking the alveoli in the lungs, the virus also infects other organs in the body, causing kidney failure, inflammation of the heart sac (pericarditis), or severe systemic bleeding from disruption of clotting system (disseminated intravascular coagulation), reduced lymphocyte cell counts (lymphopenia), inflammation of the arteries (vasculitis), and inflammation of the gut with diarrhea. People with compromised immune systems such as severe rheumatoid arthritis or organ transplantation may not experience respiratory symptoms but can have fever or diarrhea.

    How is SARS diagnosed?

    SARS-CoV is detected using enzyme-linked immunoassays (EIA) or reverse transcriptase polymerase chain reaction (PCR) tests, which are available through the CDC. These tests are performed on a sample respiratory secretions or blood.

    These tests are performed only when the patient's history makes the SARS diagnosis likely and usually in consultation with infectious-disease subspecialists, state and local public-health authorities, and the Centers for Disease Control and Prevention. If a test is positive, it will be confirmed by the CDC. Other tests may be abnormal, but they are not specific for SARS. The chest X-ray shows pneumonia, which may look patchy at first. Typically, infiltrates have the appearance of "ground glass" on computed tomography scans but may progress to frank consolidation or "white out." Lymphocyte counts in the blood are usually decreased, and platelet counts may also be low. Serum lactate dehydrogenase (LDH) and creatinine phosphokinase (CPK) levels may be increased.

    SARS should be considered in people with the appropriate symptoms who work with SARS-CoV in a laboratory or who have recent exposure to infected people or mammals in Southern China. No human cases of SARS have been reported since 2004 in the United States, so it is extremely unlikely that a patient in the U.S. will have SARS without a history of such exposure. It is possible, however, that a new outbreak might occur. Therefore, SARS (along with other similar viruses) should also be considered when there is a cluster of unusually severe viral-like pneumonia that has no other explanation.

    What is the treatment for SARS?

    Patients with SARS often require oxygen, and severe cases require mechanical ventilation. Severely ill patients should be admitted to the intensive-care unit. No medication has been proven to treat SARS effectively, and treatment is largely supportive and directed by the patient's clinical condition. In the 2002-2003 outbreak, it initially appeared corticosteroids or interferon-alpha may have been useful, but this was not confirmed and remains controversial. In the laboratory, some drugs from a group known as protease inhibitors appear effective against SARS-CoV, but these medications have not been studied in people with SARS. Management is aided by infectious-disease, pulmonary, and critical-care subspecialists. Medical caregivers need to follow strict policies on gloves, masks, gowns, and other protocols to avoid becoming infected.

    What is the prognosis of SARS?

    During the pandemic, approximately 25% of people with SARS developed severe respiratory failure or ARDS. In the general population, people with SARS had approximately a 10% chance of dying. Deaths in children were rare. However, up to 50% of people with underlying medical conditions died; people over 50 years old also had a similar death rate. Unfortunately, many people who eventually recover from SARS have had pulmonary fibrosis, osteoporosis, and femoral head necrosis and are disabled, according to reports from China.

    Is it possible to prevent SARS?

    Travelers to affected areas can protect themselves by taking simple measures that help prevent the spread of germs. Frequent hand washing with soap and water, or using an alcohol-based hand sanitizer, avoiding close contact with sick people, and not touching one's eyes, nose, and mouth can prevent the spread of viruses.

    The SARS pandemic was brought to an end by simple public-health measures. In the health-care setting, suspected cases of SARS would be placed in airborne infection isolation rooms (AIIR) such that room exhaust is recirculated with high-efficiency particulate air (HEPA) filtration. While awaiting such a room or if not available, the patient should wear a face mask and should be isolated in a single-patient room with the door closed. The number of staff assigned to the patient, and the patient's movements outside of the isolation area, should be minimized. At entry to the isolation room, health-care workers caring for the patient should wear a gown, gloves, eye shield, and a fit-tested NIOSH-certified disposable N95 filtering face-piece respirator in the room; if the latter is unavailable, a surgical mask is worn if no other care provider is available. Hand hygiene must be performed with soap and water or use an alcohol-based hand sanitizer after discarding personal protective equipment in the room and exiting.

    Mildly ill people may be cared for at home, with caregivers wearing face masks for direct care according to some clinicians, but severe illness requires hospitalization. However, other clinicians and public-health officials recommend isolation for anyone diagnosed with SARS-CoV.

    The key to preventing another outbreak is to identify the first infected patients promptly before they have time to spread the illness more widely. People who have been exposed to an infected individual should be carefully monitored for fever or respiratory symptoms. Exposure is defined as living with or caring for an infected person, being within 3 feet of the sick person, exposure to bodily fluids, or direct physical contact. The Centers for Disease Control and Prevention does not mandate quarantine measures for exposed individuals who are otherwise healthy and allows this decision to be handled on a case-by-case basis. Local public-health authorities should be consulted promptly when the diagnosis is suspected. If a significant outbreak of SARS occurs again, people may be advised to maintain a distance from others in the community ("social distancing") by avoiding large gatherings or significant close contact with others. However, isolation and quarantine methods have been effective in the prevention of SARS spread.

    What is severe acute respiratory syndrome (SARS)?

    SARS is an infectious respiratory illness caused by a coronavirus. The first cases of SARS occurred in late 2002 in the Guangdong Province of the People's Republic of China. Because of the contagious nature of the disease and the delayed public-health response, the epidemic spread rapidly around the globe. Final statistics from the World Health Organization showed 8,096 reported illnesses and 774 deaths.

    The rapid transmission and high mortality rate (about 10%) of SARS drew international attention and concern. Fortunately, efforts to identify and quarantine infected people proved highly effective. By July 2003, sustained human-to-human transmission of SARS had been eliminated. This was a public-health triumph that is often under-appreciated. Although illnesses such as anthrax or bird flu are potential threats, SARS was a very real problem. Unfortunately, future outbreaks of SARS are still possible because the virus lives in some wild bats and civets in China and also exists in laboratory cultures. In fact, there were a few human cases of SARS in 2004 as a result of laboratory accidents in the People's Republic of China. No human cases have been identified since.

    The previously unknown coronavirus that causes this syndrome was first identified in Asia in early 2003, hence its name, "SARS-associated coronavirus" or SARS-CoV. As of October 2012, SARS-CoV has been added to the National Select Agent Registry, which regulates the handling and possession of bacteria, viruses, or toxins that have potential to pose a severe threat to public health and safety. The addition of SARS-CoV permits maintenance of a national database and inspection of entities that possess, use, or transfer SARS-CoV; it also ensures that all individuals who work with these agents undergo security-risk assessment performed by the Federal Bureau of Investigation/Criminal Justice Information Service.

    Middle East respiratory syndrome coronavirus (MERS-CoV) is a new coronavirus in humans that has been identified in an outbreak in residents and travelers to the Arabian peninsula in 2012. It is not the same coronavirus as SARS-CoV, but it is similar to bat coronaviruses, and it is likely to have originated in animals as well. MERS-CoV is discussed separately in another article.

    What causes SARS? How is SARS transmitted?

    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. 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

    What are SARS symptoms and signs?

    Symptoms begin two to seven days after acquiring the virus. Initially, the illness resembles influenza and lasts for up to one week. Symptoms include fever, chills, headache, muscle aches, and poor appetite; nausea, vomiting and diarrhea are less common. This period is followed by a syndrome suggesting atypical pneumonia, including dry cough and progressively worsening to severe shortness of breath (dyspnea) and inability to maintain oxygenation (hypoxia). Progression may be rapid or it may take several days. Severely affected people develop a potentially fatal form of respiratory failure, known as adult respiratory distress syndrome (ARD or ARDS). In addition to the attacking the alveoli in the lungs, the virus also infects other organs in the body, causing kidney failure, inflammation of the heart sac (pericarditis), or severe systemic bleeding from disruption of clotting system (disseminated intravascular coagulation), reduced lymphocyte cell counts (lymphopenia), inflammation of the arteries (vasculitis), and inflammation of the gut with diarrhea. People with compromised immune systems such as severe rheumatoid arthritis or organ transplantation may not experience respiratory symptoms but can have fever or diarrhea.

    How is SARS diagnosed?

    SARS-CoV is detected using enzyme-linked immunoassays (EIA) or reverse transcriptase polymerase chain reaction (PCR) tests, which are available through the CDC. These tests are performed on a sample respiratory secretions or blood.

    These tests are performed only when the patient's history makes the SARS diagnosis likely and usually in consultation with infectious-disease subspecialists, state and local public-health authorities, and the Centers for Disease Control and Prevention. If a test is positive, it will be confirmed by the CDC. Other tests may be abnormal, but they are not specific for SARS. The chest X-ray shows pneumonia, which may look patchy at first. Typically, infiltrates have the appearance of "ground glass" on computed tomography scans but may progress to frank consolidation or "white out." Lymphocyte counts in the blood are usually decreased, and platelet counts may also be low. Serum lactate dehydrogenase (LDH) and creatinine phosphokinase (CPK) levels may be increased.

    SARS should be considered in people with the appropriate symptoms who work with SARS-CoV in a laboratory or who have recent exposure to infected people or mammals in Southern China. No human cases of SARS have been reported since 2004 in the United States, so it is extremely unlikely that a patient in the U.S. will have SARS without a history of such exposure. It is possible, however, that a new outbreak might occur. Therefore, SARS (along with other similar viruses) should also be considered when there is a cluster of unusually severe viral-like pneumonia that has no other explanation.

    What is the treatment for SARS?

    Patients with SARS often require oxygen, and severe cases require mechanical ventilation. Severely ill patients should be admitted to the intensive-care unit. No medication has been proven to treat SARS effectively, and treatment is largely supportive and directed by the patient's clinical condition. In the 2002-2003 outbreak, it initially appeared corticosteroids or interferon-alpha may have been useful, but this was not confirmed and remains controversial. In the laboratory, some drugs from a group known as protease inhibitors appear effective against SARS-CoV, but these medications have not been studied in people with SARS. Management is aided by infectious-disease, pulmonary, and critical-care subspecialists. Medical caregivers need to follow strict policies on gloves, masks, gowns, and other protocols to avoid becoming infected.

    What is the prognosis of SARS?

    During the pandemic, approximately 25% of people with SARS developed severe respiratory failure or ARDS. In the general population, people with SARS had approximately a 10% chance of dying. Deaths in children were rare. However, up to 50% of people with underlying medical conditions died; people over 50 years old also had a similar death rate. Unfortunately, many people who eventually recover from SARS have had pulmonary fibrosis, osteoporosis, and femoral head necrosis and are disabled, according to reports from China.

    Is it possible to prevent SARS?

    Travelers to affected areas can protect themselves by taking simple measures that help prevent the spread of germs. Frequent hand washing with soap and water, or using an alcohol-based hand sanitizer, avoiding close contact with sick people, and not touching one's eyes, nose, and mouth can prevent the spread of viruses.

    The SARS pandemic was brought to an end by simple public-health measures. In the health-care setting, suspected cases of SARS would be placed in airborne infection isolation rooms (AIIR) such that room exhaust is recirculated with high-efficiency particulate air (HEPA) filtration. While awaiting such a room or if not available, the patient should wear a face mask and should be isolated in a single-patient room with the door closed. The number of staff assigned to the patient, and the patient's movements outside of the isolation area, should be minimized. At entry to the isolation room, health-care workers caring for the patient should wear a gown, gloves, eye shield, and a fit-tested NIOSH-certified disposable N95 filtering face-piece respirator in the room; if the latter is unavailable, a surgical mask is worn if no other care provider is available. Hand hygiene must be performed with soap and water or use an alcohol-based hand sanitizer after discarding personal protective equipment in the room and exiting.

    Mildly ill people may be cared for at home, with caregivers wearing face masks for direct care according to some clinicians, but severe illness requires hospitalization. However, other clinicians and public-health officials recommend isolation for anyone diagnosed with SARS-CoV.

    The key to preventing another outbreak is to identify the first infected patients promptly before they have time to spread the illness more widely. People who have been exposed to an infected individual should be carefully monitored for fever or respiratory symptoms. Exposure is defined as living with or caring for an infected person, being within 3 feet of the sick person, exposure to bodily fluids, or direct physical contact. The Centers for Disease Control and Prevention does not mandate quarantine measures for exposed individuals who are otherwise healthy and allows this decision to be handled on a case-by-case basis. Local public-health authorities should be consulted promptly when the diagnosis is suspected. If a significant outbreak of SARS occurs again, people may be advised to maintain a distance from others in the community ("social distancing") by avoiding large gatherings or significant close contact with others. However, isolation and quarantine methods have been effective in the prevention of SARS spread.

    Source: http://www.rxlist.com

    Patients with SARS often require oxygen, and severe cases require mechanical ventilation. Severely ill patients should be admitted to the intensive-care unit. No medication has been proven to treat SARS effectively, and treatment is largely supportive and directed by the patient's clinical condition. In the 2002-2003 outbreak, it initially appeared corticosteroids or interferon-alpha may have been useful, but this was not confirmed and remains controversial. In the laboratory, some drugs from a group known as protease inhibitors appear effective against SARS-CoV, but these medications have not been studied in people with SARS. Management is aided by infectious-disease, pulmonary, and critical-care subspecialists. Medical caregivers need to follow strict policies on gloves, masks, gowns, and other protocols to avoid becoming infected.

    Source: http://www.rxlist.com

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