Experts have confirmed the source of infection for last year's SARS outbreak at the Taipei Municipal Hoping Hospital, according to Center for Disease Control Director General Su Ih-jen (蘇益仁).
Su yesterday said that a 47-year-old female patient at the hospital surnamed Tsao had been infected while traveling on a train with an infected tourist, surnamed Tseng, from the SARS-hit Amoy Gardens complex in Hong Kong.
Tsao was later treated at Hoping Hospital, becoming the source of the Hoping Hospital outbreak. Tseng had traveled to Taichung to visit his brother.
"We know from genetic testing that the man who visited Taichung and Tsao had contracted the same strain of the SARS virus," Su said.
Su also speculated that SARS would re-emerge every year because the virus had not been eradicated among animals, the original source of infection.
According to Su, an article written by the Chinese SARS Molecular Epidemiology Consortium in the March 12 edition of the journal Science verified that SARS was indeed a "zoonosis disease," or transmitted to humans from animals.
"Because of similarities between the animal virus and SARS, scientists had speculated that the source of the SARS infection was exotic animals," Su said.
"However, we now know for certain that despite the slight genetic differences between the animal and human strains of the virus, SARS was indeed contracted from animals," he said.
The Science article confirms that the first outbreak of SARS on Nov. 11, 2002 had resulted from contact with exotic animals.
In addition, the SARS cluster that emerged on Jan. 10 this year in China, during which a television producer contracted the virus, was also traced back to inter-species transmission.
"When the virus first attacked the human population, it went through a process of adaptation and mutation. After finding its proper niche, the virus was able to infect several people," Su explained.
But SARS symptoms were not identical from case to case, Su said.
However, Su said that all original transmissions of SARS had come from animals or from laboratories. No evidence of a human origin of infection has yet been found.
In addition, the center's labs confirmed that during the first phase of the SARS outbreak from March 14 to July 5 last year, it identified 664 possible cases of SARS; 346 patients have since been confirmed to have contracted SARS, with another 183 people ruled out. Another 135 cases remain unverifiable, with 101 of this number having died before they could be tested.
During the second phase of SARS, from July 6 last year to the end of March, one case of SARS was identified: a military researcher identified only as Lieutenant Colonel Chan. However, 1,037 cases of pneumonia were also reported.