Infectious diseases are showing up in places on the globe where they have never been before and in new hosts. These changes are a predictable result of climate change.
In an article that reviewed several years of scientific studies, researchers warned that humans can expect more diseases such as Ebola and West Nile virus to emerge in the future. This is because climate change is causing shifts in habitats that bring wildlife, crops, livestock, and humans into contact with disease-producing organisms to which they are susceptible, but to which they have never come into contact before.
At one time, biologists assumed that parasites could not jump from one species to another quickly because of the way the parasite and its host evolved. But after people hunted capuchin and spider monkeys out of existence in some areas of Costa Rica, their parasites immediately switched to howler monkeys. In recent years, lungworm parasites have shifted from caribou to musk oxen in the Canadian Arctic.
Disease-causing bacteria and viruses are able to change hosts relatively quickly. The new hosts may become sicker from the infections because they have not developed resistance.
The authors of the review article are Daniel Brooks, a zoologist with the University of Nebraska-Lincoln and Eric Hoberg, a zoologist with the U.S. National Parasite Collection of the USDA's Agricultural Research Service. Each notes that they have personally seen how climate change affected different ecosystems during their careers.
"Over the last 30 years, the places we've been working have been heavily impacted by climate change," Brooks said in a release from the University of Nebraska-Lincoln. "Even though I was in the tropics and he was in the Arctic, we could see something was happening."
Brooks and Hoberg are calling for a shift if the way science looks at disease-causing organisms, one that recognizes that they retain ancestral genetic capabilities allowing them to acquire new hosts quickly.
The article was part of a special issue on climate change of the scientific journal Philosophical Transcriptions of the Royal Society B.
