Continued climate change setting stage for rise in infectious diseases in Canada: experts

Canadian Press: ….In an article in Tuesday's issue of the Canadian Medical Association Journal, infectious disease specialists predict that global warming will increase the risk of infectious disease by expanding the geographic ranges of species known to carry diseases that jump from animals to humans. As mean temperatures rise in Canada and the rest of North America, mosquitoes and other insects known to carry diseases that can be spread to humans would likely expand their breeding areas - and also the length of time they could survive in a season, said co-author Dr. David Fisman, a scientist at the Hospital for Sick Children's research institute in Toronto.

…Fisman said it is difficult to specify a time frame for such a blooming of infectious pathogens, but he suggested such changes could occur in the next several decades. "We're not trying to predict the future," he said. "What we're saying is that there's a real possibility. Human beings are just one group of organisms that live in a really complicated ecosystem. Ecosystems include both physical and biological components and we seem to be in a situation where the physical component of the ecosystem - that is weather and climate - is changing at a rate that is faster and faster and faster."

Co-author Amy Greer, a research fellow at Sick Kids Hospital, said it is not just warmer temperatures that could play havoc with the spread of infectious diseases. "There are also a lot of predictions of ... large precipitation events - so much more rain occurring in a short period of time, which can lead to flooding," said Greer, noting that winters could be marked by more rainfall than snowfall.

…Dr. Andrew Simor, head of microbiology and infectious diseases at Toronto's Sunnybrook Health Sciences Centre, called the paper "an excellent article" and agreed there's no question that climate change will significantly influence the extent and kinds of infectious diseases that will confront humans. …

…To meet the growing infectious disease threat, Fisman and his colleagues say federal and provincial public health bodies need to strengthen the testing and surveillance infrastructure, so new cases of existing diseases and the emergence of new ones can be properly diagnosed and tracked.

…It's not just human cases that need to be monitored, said Greer, but also infectious diseases in livestock and pets. "It's becoming more apparent ... many of these pathogens do have animal or insect components to them or are pathogens that are able to be harboured by both animals and humans," she said.

"I think we like to think of ourselves as separate from our environment or animals, but I think it also calls for us to strengthen the infrastructure between the human health community and the veterinary health community."

…Besides beefing up public health infrastructure, Simor said practising physicians and medical students need to be better educated about these diseases, some of which have up to now been considered rare, subtropical infections, so they can recognize and properly treat them.

"Clearly, as if there weren't already enough reasons, this is yet another important reason to ensure that we don't contribute further to global warming," he said. "I do think this highlights how humans so very much interact with the environment, change the environment, and we're not always aware how those changes can affect us in the long run. This is an important wake-up call."

Ticks moving northward. Shown here, a life cycle diagram of ticks and Lyme disease, from the Center for Disease Control, Wikimedia Commons