Nov. 16, 2002 -- The first case of an atypical pneumonia is reported in the Guangdong province in southern China.
Feb. 26, 2003 -- First cases of unusual pneumonia reported in Hanoi, Vietnam.
Feb 28, 2003 -- World Health Organization officer Carlo Urbani, MD, examines an American businessman with an unknown form of pneumonia in a French hospital in Hanoi, Vietnam.
March 10, 2003 -- Urbani reports an unusual outbreak of the illness, which he calls sudden acute respiratory syndrome or SARS, to the main office of the WHO. He notes that the disease has infected an usually high number of healthcare workers (22) at the hospital.
March 11, 2003 -- A similar outbreak of a mysterious respiratory disease is reported among healthcare workers in Hong Kong.
March 12, 2003 -- WHO issues a global alert about a new infectious disease of unknown origin in both Vietnam and Hong Kong.
March 15, 2003 -- WHO issues a heightened global health alert about the mysterious pneumonia with a case definition of SARS as after cases in Singapore and Canada are also identified. The alert includes a rare emergency travel advisory to international travelers, healthcare professionals and health authorities.
CDC issues a travel advisory stating that persons considering travel to the affected areas in Asia (Hong Kong, Singapore, Vietnam and China).
March 17, 2003 -- An international network of 11 leading laboratories is established to determine the cause of SARS and develop potential treatments.
CDC holds its first briefing on SARS and says the first 14 suspected SARS cases are being investigated in the U.S.
March 24, 2003 -- CDC officials present the first evidence that a new strain of a virus most frequently associated with upper respiratory infections and the common cold in humans called the coronavirus might be likely cause of SARS.
March 29, 2003 -- Carlo Urbani, who identified the first cases of SARS, dies as a result of the disease. Researchers later suggest naming the agent that causes the disease after the infectious disease expert.
April 2, 2003 -- WHO issues its first travel warning recommending that all non-essential travel to Hong Kong and Guangdong province be postponed.
April 3, 2003 -- WHO-sponsored team of international infectious disease experts arrives in Guangdong province to investigate the outbreak
April 4, 2003 -- President George W. Bush adds SARS to the list of quarantinable diseases, which gives the CDC the authority to isolate persons who might have been exposed to the disease.
April 9, 2003 -- WHO investigative team gives initial report on Guangdong outbreak. The team found evidence of "super spreaders" who were capable of infecting as many of 100 persons.
April 12, 2003 -- Canadian researchers announce they have completed the first successful sequencing of the genome of the coronavirus believed to cause SARS.
April 14, 2003 -- CDC officials announce their laboratories have sequenced a nearly identical strain of the SARS-related coronavirus. The CDC version includes an additional 15 nucleotides, which provides the important beginning of the sequence.
April 16, 2003 -- A new form of a coronavirus never before seen in humans is confirmed as the cause of SARS according to Koch's postulates, which are four specific conditions that must be met for a pathogen to be confirmed as a causal agent of disease.
April 22, 2003 -- The CDC issues a health alert for travelers to Toronto, which is the epicenter of the Canadian outbreak of SARS. CDC director Julie Gerberding says the health alert alone is not a reason for potential travelers to avoid travel to the U.S. neighbor to the north, but it's part of the agency's effort to give travelers practical information to protect themselves from the global threat of SARS.
April 23, 2003 -- The World Health Organization adds Toronto, Beijing, and the Shanxi province of China to the list of regions travelers should avoid to reduce the risk of becoming infected with SARS and taking the deadly disease back home with them. WHO officials say the travel advisory will remain in effect for at least the next three weeks.
April 28, 2003 -- WHO removes Vietnam from list of SARS affected areas, making it the first country to contain SARS successfully. WHO also lifts travel advisory to Hanoi, Vietnam.
April 29, 2003 -- The WHO lifts its warning against nonessential travel to Toronto, Canada, citing local measures to stop the spread of SARS. The affected area had not reported new cases in the preceding 20 days.
May 6, 2003 -- The CDC lifts its travel advisory for Singapore because no new cases of SARS had been reported in 20 days.
May 15, 2003 -- The CDC removes its travel alert for Hanoi, Vietnam because more than 30 have elapsed since the last SARS symptoms were reported.
May 17, 2003 -- WHO extends its travel warning to include Hebei Province, China. A similar warning to postpone all non-essential travel is in effect for Hong Kong, Taipei, Taiwan, and several other areas of mainland China, including Beijing, Guangdong, Inner Mongolia, Shanxi, and Tianjin
May 20, 2003 -- The CDC lifts its travel alert for Toronto, Canada, because more than 30 days have elapsed since the last case of SARS was reported there.
May 23, 2003 -- The WHO lifts its advisory against all but essential travel to Hong Kong and the Guangdong province of China saying the SARS situation in those areas has improved significantly.
May 26, 2003 -- The WHO changes the status of Toronto, Canada, listing it as an area where SARS has recently been transmitted locally after Canadian health officials report new clusters of 26 suspect and eight probable SARS cases linked to four Toronto hospitals.
May 31, 2003 -- The WHO removes Singapore from the list of areas where SARS has been transmitted locally. It has been 20 days after the last locally transmitted case was reported.
June 13, 2003 -- WHO lifts its travel warning against nonessential travel to several provinces in China, including Hebei, Inner Mongolia, Shanxi, and Tianjin.
June 17, 2003 -- WHO lifts its travel warning against nonessential travel to Taiwan. CDC downgrades its travel warning for mainland China to a travel alert, although a travel warning from both the CDC and WHO remains in effect for Beijing.
June 23, 2003 -- WHO removes Hong Kong from its list of areas with recent local SARS transmission after 20 days passed since the last SARS case was reported and isolated, which breaks the chain of human-to-human transmission and eliminates the risk of infection for both local residents and travellers.
June 24, 2003 -- WHO removes its last remaining SARS travel warning for Beijing, China. The city was also removed from the WHO's list of areas with recent SARS transmission after 20 days passed since the last new SARS case was isolated.
June 25, 2003 -- CDC downgrades its travel SARS travel advice for Beijing, China and Taiwan from "advisory" to "alert" status, which does not advise against travel to the regions but informs travelers of a SARS health concern and advices them to take precautions.
July 2, 2003 -- WHO removes Toronto, Canda from its list of areas with recent local SARS transmission after 20 days passed since the last SARS case was reported and isolated.
July 8, 2003 -- CDC lifts its SARS travel alert for Toronto, Canada after more than 30 days had elapsed since the date of onset of symptoms for the last SARS case.
July 9, 2003 -- CDC lifts its SARS travel alert for Hong Kong retroactively to July 1 because the last SARS case there was reported on May 31.
SOURCES: World Health Organization, CDC.