Severe Acute Respiratory Syndrome By: Trent Glace Raj Patel

Background SARS stands for Severe Acute Respiratory Syndrome. The virus is a “SARS-associated coronavirus (CoV)”. This means that the virus was mutated from an animal related, SARS-like virus. Animals that the virus could possibly be adapted from include the Himalayan palm civets found in food markets and consumed as a delicacy in the People's Republic of China. SARS-CoV is thought to have evolved by positive selective pressure on animal SARS-like viruses.

Timeline November 2002- An international outbreak involving 26 countries, 8439 cases, and 774 deaths. March 2003- The outbreak is starting to be recognized by the WHO. Severe Acute Respiratory Syndrome is identified. Global alert issued after cases move to Canada. April 2003- The RNA of the virus is isolated and replicated. May 2003- Source of virus is identified from animals sold for human consumption. June 2003- Many cities are removed from the list of possible infected cities. July 2003- The outbreak finally culminated.

Taxonomy Prior to the discovery of SARS-CoV, only two coronaviruses were recognized as causing human disease. Coronavirus OC43 and 229E, both associated with the common cold. Coronaviruses can be divided into three groups based on their genetic and protein content. SARS-CoV does not fit into any of these three groups and is new virus.

Taxonomy The coronavirae is a group of viruses that are typically spherical and have specific receptors that bind to a cell. The virus enters a cell the typical way of any other virus.

Diagnosis Multiple tests for the diagnosis of SARS have been developed. Reverse transcription–polymerase chain reaction (RT-PCR), which detects SARS-CoV RNA in specimens of blood, stool, and respiratory secretions taken from patients Serologic tests, which detect SARS-CoV antibodies in the serum produced after infection, have become the mainstay of laboratory diagnosis. SARS appears to be less sensitive to Seroconversion (development of antibodies to a particular antigen) occurs in patients with SARS from 1 to 4 weeks after symptom onset. The majority of patients do not develop either immunoglobulin G (IgG) or IgM antibodies until the third or fourth week of illness.

Symptoms The SARS CoV is typically inhaled from an environment and introduced to the lungs and gastrointestinal tissues of a host. The virus attaches to the lungs. This produces an influx in enzymes, Angiotensin-converting enzyme 2, which is predominantly found in the heart and kidney, is a cellular receptor for SARS-CoV. Since SARS thrives in the lungs it causes symptoms very similar to pneumonia.

Symptoms Typically a host develops a fever first, sometimes in excess of 100.4°F (38.0°C). The fever is sometimes associated with chills or other symptoms, including headache, general feeling of discomfort, and body aches. Some people also have mild respiratory symptoms at the outset. About 10 percent to 20 percent of patients have diarrhea. After 2 to 7 days, SARS patients may develop a dry, nonproductive cough or feel short of breath. These symptoms might be accompanied by or progress to a condition in which the oxygen levels in the blood are low (hypoxia). Most patients develop pneumonia eventually.

Tests SARS CoV cannot be readily identified. One technique is a white blood cell count Other tests identify the number of enzymes lactate dehydrogenase and creatinine kinase. The virus produces high levels due to lung tissue damage. A chest radiograph produses infiltrates (typically in 2nd week to 3rd week). Lastly, high-resolution computerized tomography can be used to identify viruses.

Transmission Human Animal Direct contact with mucosal membranes Respiratory droplets Airborne transmission through fomites Close contact Consumption of various other infected organisms.

Epidemiology SARS is only contained in laboratories where the virus is being studied. Animals carry non-lethal forms from which the virus was originally mutated.

Morbidity and Mortality Death only occurs for every 1 : 10.46 people. SARS is treated by actively caring for the infected and allowing them to make their own antibodies (takes about 3 weeks to fully complete) SARS in children is less virulent and rarely kills the host. The last international outbreak, involved 26 countries, 8098 cases, and 774 deaths. Ended in July 2003. Since then, there has been one cluster of 11 cases including one death, resulting from the “escape” of SARS-CoV from research laboratories. In addition, four isolated cases of SARS with no deaths were identified in December 2003 and January 2004.

Pathogenecy Recently, the 29,751-base pair long genome for SARS-CoV was fully sequenced. Scientists are currently conducting a thorough investigation of the sequence to identify any types of vaccines that may be used for possible preventive techniques.

Works Cited "CDC- Fact Sheet for SARS." Severe Acute Respiratory Syndrome (SARS). 3 May 2005. Department of Human and Health Services. 9 Dec. 2007 <http://www.cdc.gov/ncidod/sars/factsheetcc.htm>.   Kleinman, Arthur. SARS in China: Prelude to Pandemic? California: Stanford: Stanford UP, 2006. 240-244. Poutanen, Susan M. "McGraw Hill-Access Science." 7 Dec. 2007 <http://www.accessscience.com.ezaccess.libraries.psu.edu/content.aspx?id=YB051720>. "The Genome Sequence of SARS Associated Corona virus." 30 May 2003. Science Express. 5 Dec. 2007 <http://www.sciencemag.org/cgi/content/abstract/300/5624/1399>.