A new study has found that as the climate continues to warm, we will be dealing with more infectious and parasitic diseases. Ultimately, we’ll have to face numerouse separate epidemics caused by climate change, researchers say.

Image via WHO.

It seems like with climate change, it’s more an issue of what gets us first – will it be the drought, the rising sea levels or… the diseases? Daniel Brooks, an eminent zoologist from the University of Nebraska-Lincoln’s Harold W. Manter Laboratory of Parasitology says that outbreaks like the recent Ebola epidemic will become more and more common as the climate continues to warm. Professor Brooks says it will be ‘the death of a thousand cuts’ with society unable to keep up with the speed of disease as it spreads throughout the world – it won’t be one major outbreak, but several smaller ones.

“It’s not that there’s going to be one ‘Andromeda Strain’ that will wipe everybody out on the planet,” Brooks said, referring to the 1971 science fiction film about a deadly pathogen. “There are going to be a lot of localized outbreaks putting pressure on medical and veterinary health systems. It will be the death of a thousand cuts.”

Brooks has focused mostly on the tropical areas, while his colleague and co-author Eric Hoberg, a zoologist with the U.S. Department of Agriculture’s National Parasite Collection, focused mainly on Arctic regions. Both have observed how the changing climate is affecting disease development, and both have concluded that global warming will cause more and more infectious diseases.

“Over the last 30 years, the places we’ve been working have been heavily impacted by climate change,” Brooks explained in an interview last week. “Even though I was in the tropics and he was in the Arctic, we could see something was happening.”

Changes in climate also allow parasites and parasite hosts to migrate to different areas. For example, some lungworms in recent years have moved northward and shifted hosts from caribou to muskoxen in the Canadian Arctic, something which was previously considered impossible.

“Though a parasite might have a very specialised relationship with one particular host in one particular place, there are other hosts that may be as susceptible,” Professor Brooks said. “West Nile Virus is a good example of this phenomenon – no longer an acute disease problem for humans or wildlife in North America, it nonetheless is here to stay,” he said.

This is the so-called “parasite paradox”. In time, both parasites and hosts become more adapted to each other and become better at fighting each other, so a type of stalemate is reached. But Brooks believes that parasites will break the equilibrium first, mutating into more dangerous versions. In order for society to maintain the upper hand, there needs to be a tight collaboration between veterinarians, public health officials, and biologists, says Brooks. For example, becoming aware of the way non-human carriers of a pathogen behave and are distributed could lead to better-informed public health strategies. But the problem remains that we are not leading this fight – we’re simply reacting.

“We have to admit we’re not winning the war against emerging diseases,” Professor Brooks said. “We’re not anticipating them. We’re not paying attention to their basic biology, where they might come from and the potential for new pathogens to be introduced.”

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