Severe acute respiratory syndrome

Posted by e-Medical PPT
Severe acute respiratory syndrome is a respiratory disease in humans which is caused by the SARS coronavirus.Coronaviruses are positive-strand, enveloped RNA viruses that are important pathogens of mammals and birds. This group of viruses cause enteric or respiratory tract infections in a variety of animals including humans, livestock and pets.Initial symptoms are flu-like and may include: fever, myalgia, lethargy, gastrointestinal symptoms, cough, sore throat and other non-specific symptoms. The only symptom that is common to all patients appears to be a fever above 38 °C (100.4 °F). Shortness of breath may occur later.
SARS may be suspected in a patient who has:
   1. Any of the symptoms, including a fever of 38 °C (100.4 °F) or higher, and
   2. Either a history of:
         1. Contact (sexual or casual) with someone with a diagnosis of SARS within the last 10 days OR
         2. Travel to any of the regions identified by the WHO as areas with recent local transmission of SARS
A probable case of SARS has the above findings plus positive chest X-ray findings of atypical pneumonia or respiratory distress syndrome.White blood cell and platelet counts are often high.
Three possible diagnostic tests have emerged, each with drawbacks. The first, an ELISA (enzyme-linked immunosorbent assay) test detects antibodies to SARS reliably but only 21 days after the onset of symptoms. The second, an immunofluorescence assay, can detect antibodies 10 days after the onset of the disease but is a labour and time intensive test, requiring an immunofluorescence microscope and an experienced operator. The last test is a polymerase chain reaction (PCR) test that can detect genetic material of the SARS virus in specimens ranging from blood, sputum, tissue samples and stools. The PCR tests so far have proven to be very specific but not very sensitive.M


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