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SARS

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WHO reported SARS through 31-Mar-2003
Country Cases Deaths
Canada 44 4
China, Mainland 806 34
China, Hong Kong 530 13
Taiwan 10 0
France 1 0
Germany 5 0
Italy 2 0
Ireland 2 0
Romania 3 0
Singapore 92 4
Switzerland 3 0
Thailand 5 1
United Kingdom 3 0
United States (+) 59 0
Vietnam 58 4
Total 1623 60
(+) Due to reporting differences, United States
cases reflect suspected instead of probable cases.


Severe acute respiratory syndrome (SARS) is an atypical pneumonia that first appeared in Guangdong, China in late 2002. Reports of the disease did not reach international health-agencies until it had spread to Hong Kong and Vietnam. The disease was first recognized by World Health Organization doctor Carlo Urbani, who later died of the disease in Thailand on March 29, 2003.

The illness has thusfar caused death in about 3.5% of known cases. Disease transmission is not completely understood, but is suspected to be via inhalation of droplets expelled by an infected person when coughing or sneezing; the possibility exists that it may also be transmitted via contact with secretions on objects.

Current state of knowledge regarding etiology of SARS

The etiology of SARS is still unknown.

Initially, electron microscopic examination in Hong Kong and Germany found viral particles with structures suggesting paramyxovirus in respiratory secretions of SARS patients; subsequently, in Canada, electron microscopic examination found viral particles with structures suggestive of metapneumovirus (a subtype of paramyxovirus) in respiratory secretions. The United States Centers for Disease Control and Prevention (CDC), however, noted viral particles in affected tissue (finding a virus in tissue rather than secretions suggests that it is actually pathogenic rather than an incidental finding). On electron microscopy, these tissue viral inclusions resembled coronaviruses, and PCR testing suggested that they were a previously unrecognized coronavirus. A test was developed for antibodies to the virus, and it was found that patients did indeed develop such antibodies over the course of the disease, which is very suggestive that the virus does have a causative role. Findings, however, remain preliminary: further work, such as a comparison of the viral strains from all patients, remains to be done, and other etiologic possibilities may be revealed through continued study.

China has forbidden its press to report on the disease, and it has generally lagged in reporting the situation to the World Health Organization, delaying the intitial report for 4 months and so far has reported statistics only through the end of February. Initially, it did not provide information for Chinese provinces other than Guangdong, the province where the disease is believed to have originated. [1]

Symptoms and treatment

On March 12, 2003, the WHO issued a global alert, followed by a health alert by the CDC. WHO recommends that suspected cases be treated in isolation, and defined a suspected case as a person presenting after February 1, 2003 with history of:

  • high fever of >38° C (100.4° F) -and-
  • one or more respiratory symptoms including cough, shortness of breath, difficulty breathing, hypoxia, or pneumonia -and-
  • one or more of the following:
    • close contact with a person suspected of having SARS -or-
    • recent history of travel to areas with documented transmission of SARS

In addition to fever and respiratory symptoms, SARS may be associated with other symptoms including headache, muscular stiffness, loss of appetite, malaise, confusion, rash, and diarrhea. The count of white blood cells and platelets is often low. Symptoms usually appear within 10 days after infection. In severe cases, patients have to be put on a ventilator.

Antibiotics are ineffective. The antiviral drugs ribavirin or oseltamivir may have some efficacy, and the role of steroids in treatment remains to be determined. The CDC is testing antiviral drugs against coronaviruses to see if specific recommendations can be formulated.

Progress of the outbreak

At the end of February 2003, an Chinese-American businessman visiting Guangdong travelled via Hong Kong to Hanoi, Vietnam, where he was admitted to a hospital. After the disease was transmitted to a number of hospital workers there, he was returned to Hong Kong (to be treated along with other cases) where he died. In a separate outbreak in the Hong Kong Prince of Wales Hospital in March, at least 68 hospital workers were infected.

Almost all of those infected to date have been either medical staff or family members of people who have fallen ill. It is believed that all affected medical staff were not using respiratory precautions, a safety protocol that should fully protect medical workers, at the time of exposure. The various cases around the world are directly or indirectly traceable to people who have recently visited Asia.

In November 2002 an outbreak of what is believed to be the same disease began in the Guangdong province of China, which borders on Hong Kong. Of the 806 people reported infected, at least 34 died. This outbreak peaked in mid-February 2003, at which time the World Health Organization (WHO) was notified. Chinese authorities are now working with WHO investigators to determine if the Guangdong outbreak is related to SARS.

About 80% of the Hong Kong cases have been traced to a Chinese doctor who had treated cases in Guangdong, checked into the Hong Kong hotel Metropole, and infected seven other guests before dying on March 4. These seven people went on to infect hospital personnel.

On March 20, WHO reported that several hospitals in Vietnam and Hong Kong were operating with half the usual staff, because many workers stayed home out of fear of getting infected. WHO raised the concern that substandard care of the infected patients may contribute to the spread of the disease.

On March 25, Hong Kong authorities said nine tourists came down with the disease when a mainland Chinese man infected them on a March 15 Air China flight to Beijing.

Action to try to control SARS

Using electron microscopes, virologists in Germany and Hong Kong independently identified virus particles in specimens from infected patients. Initially, it was thought that the identified virus belongs to the paramyxoviridae family, but later studies by the CDC suggested that it is a coronavirus. Another possibility is that coinfection by both viruses is required. Sequencing of the virus genome is ongoing.

WHO set up a network for doctors and researchers dealing with SARS, consisting of a secure web site to study chest x-rays and a teleconference.

Attempts are being made to control further SARS infection through the use of quarantine. In Singapore and Hong Kong, schools were closed for 10 days to contain the spread of SARS. [2]

On March 27, 2003, the WHO recommended the screening of airline passengers for the symptoms of SARS. [3]

References

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