Toronto's latest outbreak(s):
As of May 24, PM, there were 33 patients who became sick in the recent cluster, or what may be two clusters. There is no epidemiologic link -- the first patients to get sick had no known contact with any SARS cases.

These 33 became sick gradually over the past month, with never more than 2 or 3 new cases in a single day. The first illness in the cluster(s) began on April 22. The new cases developed through the period that WHO placed a travel advisory against Toronto and then lifted the advisory, one week later. The city undertook a major advertising campaign, to lure tourists "back" to Toronto, over the past 3 weeks. That campaign is now on hold -- another provincial emergency will be declared tomorrow.

Before about May 22, SARS was apparently not diagnosed in any of these cases, despite the fact that several cases were fairly typical of SARS -- except for the absence of an epidemiologic link to a previous SARS case.

The patients became ill or contracted SARS at North York General Hospital, St. John's Rehabilitation Hospital, the neurosurgery unit of St. Michael's Hospital, and the Baycrest Centre for Geriatric Care.

By May 25, news reports were estimating the cluster(s) involved at least 40 patients, 2 of whom have died. Three more remain in critical condition, including a physiotherapist who contracted the illness from her patient at North York General Hospital. Nine or ten health care workers are ill, plus some family members, and hospital vistors.

More details and a timeline are available in today's SARS Update, on the Agonist's SARS bulletin board.

China's silence on SARS cost lives and allowed the epidemic to grow:
China Airlines and Chinese government officials appear to have not learned the lesson about SARS, that openness and transparency are important to control the epidemic.
Boston Globe, May 25: Exploring China's silence on SARS--New details surface on initial cover-up.

Twenty-one cases of people who had contracted severe acute respiratory syndrome, including three passengers who died, after flying March 15 on Air China Flight 112 from Hong Kong to Beijing. A 72-year-old man with SARS was on the flight. He is said to have spread the virus to other passengers. It then spread to Hong Kong, Taiwan, Singapore, Beijing, Inner Mongolia, and beyond...

Some victims sat five to seven rows from the sick man, well beyond the accepted ''close contact'' risk area for SARS, said Dr. Max Hardiman, WHO's chief for international health regulations...

Eleven days after Zhu -- a senior Commerce Ministry official -- was hospitalized in the SARS ward of Beijing's Ditan Hospital on March 26, health officials announced the death of Pekka Aro, the 52-year-old Finn, at the same hospital, but said his illness could not be linked to anyone in China.

''He probably contracted it abroad, but fell ill after arriving in Beijing,'' Guo Jiyang, deputy director of the Beijing Health Bureau, said at a news conference on April 6.
...In the last week of March, authorities traced people aboard the March 23 Thai Air flight on which Zhu sat next to Aro, indicating that Guo and other health officials should have known how Aro contracted the disease -- and could have warned him. Believing he had the flu, Aro delayed seeking treatment and died...

Civet cats -- an animal reservoir or source of human SARS:
Straits Times, May 25:

WHO expert Francois Meslin, responding to new evidence that found the Sars virus in three small mammals,including a civet cat that is eaten as a delicacy by some, said: 'It's certainly too early to draw final conclusions on those findings but they are clearly quite exciting.'...

While one species may be the reservoir, others can be what are known as 'amplification hosts', whereby they are infected by the reservoir species and then pass on the bug to humans.

'We cannot say those animals are the source of the initial cases of Sars,' Dr Meslin said.

'We really need to investigate more the relationship between the different animal species found to have the virus, and maybe others.

'These animals can consume small mammals, particularly rats and mice, and those could be the source of the infection, so for the time being, it's all conjecture,' he said.

Compared to the coronavirus found in the masked palm civets (civet cats), SARS-CoV (the virus that causes SARS in humans) has a 'deletion' of 29 nucleotides from its genetic code and a resulting 'frame shift' of the genetic code. This finding in the genetic code makes it much more likely that the virus passed from a civet to humans, rather than the other way.

ChannelNewsAsia, May 25: "The findings suggest that the form of the coronavirus that is suspected to have jumped from either the civet cat or the raccoon dog to humans was less lethal than the SARS coronavirus transmitted from human to human... After jumping from the animals, the SARS virus underwent changes that made it more lethal to humans, researchers said."

The finding of antibodies to SARS in a number of animal traders supports an animal origin of SARS. It is possible, however, that these Guangdong animal traders caught SARS from a human contact. More evidence is needed to show that animal traders are more likely to carry SARS antibodies, compared with the general populace in Guangdong.

Click here to read the full SARS Update.