Scientists race to identify deadly illness
Apr 24, 2009 04:30AM
Megan Ogilvie, Health Reporter
Canadian health officials are spearheading efforts to identify the severe respiratory illness that has baffled Mexican authorities, put hundreds in hospital and killed at least 20 otherwise healthy young adults.
The National Microbiology Laboratory in Winnipeg has received 51 samples from Mexico – with more expected to come – and scientists are working to quickly identify the flu-like illness, according to officials from the Public Health Agency of Canada. Results of the laboratory tests could be expected as early as today.
Since March 18, there have been 137 cases of severe respiratory illness, or SRI, reported in Mexico and 20 deaths in a four-week span.
There have been no confirmed cases of the illness outside Mexico, but Canadian health officials are asking public health units, quarantine units and health care providers to be on the lookout for SRI, particularly in people returning from Mexico in the last two weeks.
At least one case – a person from Ontario who returned from Mexico, was diagnosed with SRI on March 22 and who has since fully recovered – is currently under investigation by provincial authorities, said Dr. Danielle Grondin, acting assistant deputy minister for infectious disease and emergency preparedness, at a press conference yesterday.
At this time, officials do not believe the Ontario case is related to the illness in Mexico, she said.
The Public Health Agency of Canada has raised the pandemic surveillance alert from a Level 1 to a Level 2. Grondin said this was "not common" but stressed the move was to signify their increased level of vigilance.
The agency said it planned to issue a travel advisory to Mexico yesterday evening, which would warn potential travellers to protect themselves from influenza as they would anywhere else at home and abroad. Grondin said these precautionary measures include getting the seasonal flu vaccine, regularly washing hands and covering coughs.
Canadian health officials are also concerned about seven cases of human swine influenza in the United States – five cases in California and two in Texas. All seven cases have fully recovered, Grondin said. Some cases were the result of human-to-human transmission. Dr. Allison McGeer, director of infection control at Mount Sinai Hospital, said the surveillance alerts from Mexico and the advisories sent by Canadian public health officials are the appropriate response.
"We should be celebrating the level of transparency of communication, the speed with which this is happening," she said. "This is an excellent marker for how things have gotten better since SARS in terms of us being able to co-ordinate things internationally and figure out what is going on." In Mexico, infected individuals first reported flu-like symptoms, which rapidly progressed to severe respiratory distress in about five days. Most cases occurred in otherwise healthy young adults between the ages of 25 and 44, which health officials say caused the concern since influenza is most often deadly for the elderly and people with compromised immune systems.
The majority of the 137 cases occurred in Mexico City and some of the cases have tested positive for influenza A and B viruses. A press release issued yesterday by the Mexican health authority suggested the spike in illnesses was due to end-of-season flu activity and stressed there is not an epidemic.
It is not yet clear if the cases represent an outbreak due to a single organism or whether they represent a coincidental spike in isolated cases, said Dr. Andrew Simor, head of microbiology and infectious diseases at Sunnybrook Health Sciences Centre.
"At this time, there is nothing to indicate there is a new virulent strain of virus that is currently circulating globally," he said.
With files from Tanya Talaga