Plague is an ancient disease caused by the bacterium Yersinia pestis that continues to sicken and kill people even in the 21st century. Since 2000, most of the outbreaks of plague have occurred in Africa.

A new study published in the American Journal of Tropical Medicine and Hygiene (AJTMH) found the push to boost food production that is accelerating the conversion of natural lands into croplands in Tanzania may be significantly increasing the risk of plague.  Researchers studied rodents in northern Tanzania, where croplands have expanded by 70 percent over the last few decades.  They discovered that where maize production has been introduced, the number of rodents infested with plague-carrying fleas that can cause human infections nearly doubled compared to numbers in neighboring forest areas.

“Introducing maize production in natural areas appears to create a perfect storm for plague transmission,” said Hillary Young, PhD, a community ecologist at the University of California, Santa Barbara, and one of the lead authors of the study. “The presence of the crop as a food source caused a surge in the population of a rat species known to carry plague. Local farmers often then store this harvested corn next to or inside their homes—baiting in the hungry field rats and increasing opportunities for human infection.”

“These kinds of conditions are what breed outbreaks,” Young said.

To read more about the study’s findings, check out these articles:

Africa’s expanding farms attract more plague-infested rats — Reuters

Good News: More Crops! Bad News: More Plague! — NPR “Goats and Soda”

Growing Corn in East Africa Is Attracting More Plague-Carrying Rats —Motherboard (VICE.com)

Rats Pose Plague Risk in Croplands — Voice of America

Mo’ Farms, Mo’ (Plague) Problems — Discover Magazine “Body Horrors” blog

Kans op pest stijgt in Afrika — KIJK Magazine (Netherlands)