Infectious diseases jumping to new organisms in warming Arctic

A changing climate means a changing landscape for infectious diseases — including in the Arctic — but those changes, if studied, are predictable.

That’s according to a new study about the evolution of emerging infectious diseases by two scientists from the United States.

These diseases occur when parasites switch hosts, spreading the disease to new types of organisms.

Daniel Brooks, of the University of Nebraska, and Eric Hoberg, from the Beltsville Area Research Centre, argue that planning ahead and managing the risk is the most effective way forward in their paper, “Evolution in action: climate change, biodiversity dynamics and emerging infectious disease.”

“Just as we cannot stop climate change, we cannot stop these emerging diseases. We believe, however, that proactive risk management is less expensive and thus more effective, than responding after the crisis,” the scientists wrote in an article published this month by The Royal Society.

But this approach requires scientists to rethink how parasites adapt to find and colonize new hosts — organisms in which parasites live and multiply — the scientists said.

For the past 100 years, “humanity has tended to react to emerging diseases as they occur… in an attempt to mitigate the damage done.”

That reactive approach was based largely on the assumption that the relationship between parasite and host is very specific and therefore parasites cannot easily or quickly find new hosts to infect.

But Brooks and Hoberg believe that parasites may have more flexibility than assumed — especially during periods of climate change.

And they draw on studies of parasites called lungworm nematodes in the caribou and muskox populations of western Nunavut’s Victoria Island as a modern day example.

Nematode parasites were unknown to these herds until 2008 and 2010 for muskox and caribou, respectively.

The parasites infecting the migratory caribou were likely brought back to Victoria Island from the mainland for decades, the scientists said, but it wasn’t until recently that warmer temperatures allowed the parasite to thrive north.

A number of factors, including warmer temperatures, likely coincided with the parasites ability to survive north of the mainland.

“Climate warming, in both cases, is a central driver in expanding distributions and successful establishment of the parasites on the island,” Brooks and Hoberg wrote.

The scientists said a framework for managing emerging infectious diseases could complement the usual practice of reacting to emerging diseases as they occur — depending on the specific parasite’s flexibility.

“The planet is thus an evolutionary and ecological minefield of [emerging infectious diseases] through which millions of people, their crops and their livestock wander daily,” Brooks and Hoberg wrote.