Noroviruses are part of a group of viruses that cause the stomach flu and the health authority says they are common in long-term care homes and are spread by people who don't wash their hands.
Yet, Dr. Richard Stanwick, the chief medical health officer, says the outbreak that began July 11 is unusual.
He says most outbreaks start with a couple patients, are limited to a single floor and can be contained.
But Stanwick says the virus affected 40 people at the start of the outbreak and that allowed it to impact the entire institution.
He says officials have been unable to identify a common source of exposure. (News 1130)
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