Publication Date July 27, 2017

Climate change could lead to more infections from parasitic worms

Mizzou researchers studied fossils of clams called Abra segmentum valves that had been infected by trematodes, collected from nothern Italy. Photo: Scientific Reports

Fossil records suggest that there could be another consequence of climate change and rising sea levels: an increase in parasitic worm infections. 

Scientists at the University of Missouri-Columbia and the University of Bologna studied clams collected in northern Italy that date back to the Holocene Epoch, a time when the planet was warming up after the Ice Age. Parasitic worms called trematodes, also known as flukes and flatworms, would attempt to feed on these ancient clams and the clams would respond by developing pits to keep them out.

By looking at the pits, the researchers learned that the presence of trematodes increased during relatively short periods of sea level rise.

"Based on what we know of these sediments, these were processes happening on the scale of hundreds of years, rather than thousands," said John Huntley, a paleontologist at Mizzou. 

The changes happening over shorter time scales could imply that the risk of getting infected by trematodes could increase due to climate change. The worms can spread diseases, including schistosomiasis, which affects more than 200 million people in subsaharan Africa, the Middle East, southeast Asia and the Caribbean. 

Huntley said that the evidence suggests that parasitic infections could rise in coastal environments, which could raise public health concerns. 

"If we do see an increase in these parasites, that's going to be fundamentally challenging for some of these coastal ecosystems," Huntley said. "We rely upon them greatly for transportation, recreation, for food." 

However, researchers haven't figured out how sea level rise could increase infections from parasitic worms. Huntley's team recently received a grant from the National Science Foundation to help understand that connection.

[Related study available here]