In November 2002, the first case of what would eventually be known as SARS was reported in Guangdong, China. By February, China was reporting an outbreak to the World Health Organization.
As the virus spread to Hong Kong and onward to other countries, it resulted in more than 800 deaths worldwide, including 44 in Canada.
SARS “appeared out of nowhere” said Dr. Amesh Adalja, an infectious disease physician and senior scholar at the Johns Hopkins Center for Health Security who studies pandemics.
In this case, at least, it was maybe typical.
“The bottom line is most of the next emerging pathogens will be totally unpredictable,” said Dr. Theresa Tam, Canada’s Chief Public Health Officer.
“We can be watching all we like but we need to have systems that are flexible, scalable, can detect more hazards, so that if something does come up, we have the ability to rapidly identify what it is and do something about it.”
And doctors are watching. A global network of researchers, including the WHO, are constantly looking for emerging threats. Things hit their radar when they’re “unusual or unexpected,” said Tam. “By unusual or unexpected, maybe unusually severe. Unusual in its location. Unusual in its presentation.”
Once they have something unusual, researchers assess the danger.
What makes a virus dangerous
A number of characteristics make for a virus that’s ready to wreak havoc among the population.
First, it has to spread easily, said Adalja — ideally through the air.
Jennifer Ganton, an associate professor at UBC’s School of Population and Public Health and Canada Research Chair in Public Health Genomics, said that people are most likely to catch a virus like measles, which lingers in the air for hours, or like influenza, which spreads through water droplets.
A dangerous virus also has to be severe.
“If you want to do real damage, Contagion film-style damage, you want a virus that is going to wreak havoc on the body,” she said.
It also needs to occur in the right place, with lots of people around, she said. SARS happened in one of the most populous regions on Earth. “That was a spillover event where a virus jumped into a setting where you’ve got millions of susceptible hosts.”
It helps too if the virus is novel enough — coming from an unusual animal source, for example — for people to have very little immunity to it, she said.
An extra-sneaky virus can be spread during the incubation period, before someone even shows symptoms, said Adalja. “We know that when you have infections that are spread during the incubation period, when people are not sick, it can allow that virus to really spread all over the place.”
Fighting the plague
Ganton isn’t worried about Canada’s ability to fight the next big pandemic. “There will always be pandemics. We will always be surprised,” she said.
Canada has the laboratories, surveillance, expertise and plans to effectively meet a public health threat from a new disease, she thinks.
“If some severe patient ends up in hospital in Canada with some unknown disease, we’re going to be investigating that person and we’re going to find out what it is,” Tam said.
She believes this could happen in as few as 48 hours.
Canadian experts, like those at the National Microbiology Lab in Winnipeg, are called upon to identify viruses worldwide. In 2009, as the first cases of H1N1 influenza appeared in Mexico, Mexico wanted Canada to look into it.
“I think the presidential plane flew into Winnipeg from Mexico and dropped the vials,” she said. Canada was the first to sequence the DNA of the virus, an important step in figuring out how to fight it.
Canada has plans to deal with specific diseases as well as plans that can be applied to any situation, she said.
“You can never be completely prepared for the next Disease X, but we’re doing as much as we can to get there.”
Ganton believes that surveillance is the best way to prevent the next pandemic – not predicting the next big virus. “It’s just going to be much better surveillance systems.”
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