(CNN)Here's some background information about SARS, severe acute respiratory syndrome. Since 2004, there have been no known cases of SARS reported anywhere in the world.
SARS is an acute viral respiratory illness brought on by a coronavirus.
Symptoms include fever, cough, severe headache, dizziness and other flu-like complaints.
The illness presents as an atypical pneumonia that does not respond to standard treatments.
There were 8,098 confirmed cases of SARS from November 2002 to July 2003, with 774 deaths.
November 16, 2002 - What will become known as SARS is first reported in Foshan, China.
November 2002-February 2003 - Five people die and more than 300 are reported ill of SARS in Guangdong province, China.
February 15-22, 2003 - Liu Jianlun develops SARS symptoms on a trip from Huang Xingchu in the Guangdong province to visit family in Hong Kong. He is considered patient zero, or the first person to die of the disease. He infects people at his hotel and his family. He is hospitalized and dies, as does one member of his family.
March 15, 2003 - The World Health Organization (WHO) issues an emergency travel advisory about the illness, calling it a "global threat."
March 27, 2003 - Hong Kong officials have quarantined more than 1,000 people and schools close in Singapore.
March 29, 2003 - Dr. Carlo Urbani, the WHO physician who identified SARS in patient zero, dies from the virus in Bangkok.
April 1, 2003 - An American Airlines flight from Tokyo is quarantined at Mineta San Jose Airport. Three passengers are transported to an area hospital for evaluation of SARS and later released.
April 4, 2003 - By executive order, President George W. Bush has SARS added to the list of communicable diseases for which a person can be quarantined.
April 14, 2003 - Working independently, American and Canadian scientists announce they have sequenced the genome thought to be the cause of SARS.
April 20, 2003 - China cancels a weeklong national holiday celebration as Beijing's SARS cases rise from 37 to 339 in less than a week. A wholesale vegetable market in Singapore closes and all 2,400 people are quarantined.
April 22, 2003 - The CDC issues a health alert for travelers in Toronto.
April 23, 2003 - Travel warnings and advisories for Shangxi province, Beijing and Toronto have been increased and those for Hong Kong and Guangdong province have been extended.
April 28, 2003 - WHO lists Vietnam as the first nation to contain the SARS outbreak.
April 29, 2003 - WHO announces it will lift its SARS advisory against travel to Toronto.