WHO: SARS outbreaks contained
(CNN) -- The World Health Organization has declared the SARS virus outbreak contained around the world after removing Taiwan, the last region on its list of affected areas.
The island, which had seen soaring numbers of infections in May, has not reported a single new case during the past 20 days -- the benchmark figure by which an outbreak can be judged contained.
Announcing Saturday that the global outbreak had been contained, WHO Director General Dr. Gro Harlem Brundtland warned countries around the world not to let down their guard against the virus, saying they must remain vigilant against the disease which has claimed 812 lives.
"Today is a milestone," she said, but it came with the warning that "the world is not SARS free."
"There are still close to 200 SARS patients in hospitals," Brundtland said in a statement from WHO headquarters in Geneva. "It is possible that cases have slipped through the net."
SARS is thought to have originated in southern China, where the first known cases began appearing last November.
From China, experts believe the flu-like illness was carried to Hong Kong, Vietnam and Singapore, eventually traveling as far as South Africa and Canada infecting at least 8,400 people.
In some of the worst-affected areas, such as Hong Kong, streets full of pedestrians wearing surgical face-masks became an everyday sight.
In Taiwan, which initially appeared to have fended off the virus, cases began to soar in April following failings in the island's health care system.
Misdiagnosis of cases and the failure to quarantine infected patients were two key factors that led to Taiwan becoming the world's number three SARS hotspot.
Since the introduction of tighter health measures the island has not had a single case since June 15.
Although the virus has now been contained, the WHO said much remains unknown about it, including its origin and the most effective treatment methods.
Its statement went on to call for continued research into the respiratory illness, including the hunt for a possible animal reservoir for the virus.
The statement also called on governments around the world to boost their public health systems and monitoring networks in preparation for a possible new outbreak.
Health officials have expressed fears that SARS may make a comeback, possibly in an ever more powerful form, with the return of the northern hemisphere winter.
Dr. David Heymann, WHO's executive director of communicable diseases, emphasized the continued urgency saying: "A false sense of security could become our worst enemy."