Africa's expanding farms attract more plague-infested rats

by Chris Arsenault | @chrisarsenaul | Thomson Reuters Foundation
Monday, 23 February 2015 22:00 GMT

A boy displays boiled rats for sale on the main highway in Malawi's capital Lilongwe June 20, 2009. REUTERS/Thomas Mukoya

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Scientists link increase in corn fields in northern Tanzania to 20-fold rise in population of African rats

ROME, Feb 23 (Thomson Reuters Foundation) - Converting wilderness areas into farmland in East Africa may be increasing the risk of disease epidemics, as rodents crawling with plague-carrying fleas are drawn to the harvested food.

In northern Tanzania, crop lands have expanded by 70 percent over the last few decades and the number of plague-carrying rodents in these corn growing lands has nearly doubled compared with neighbouring wilderness areas, said the study published in the American Journal of Tropical Medicine and Hygiene on Monday.

Scientists linked an increase in corn fields - necessary to feed an expanding population - to a 20-fold rise in the population of African rats in northern Tanzania, which transmit deadly diseases to humans, including Lassa fever and plague.

"We found that introducing maize production in natural areas appears to create a perfect storm for plague transmission," Hillary Young, a University of California professor and a lead author of the study, said in a statement.

"Local farmers often ... store this harvested corn next to or inside their homes - baiting in the hungry field rats and increasing opportunities for human infection."

In Tanzania alone, plague caused about 675 deaths from 1980 to 2011, the study said, and these numbers could rise as new wilderness areas become farmland and rat populations increase.

Though less deadly than Ebola or other epidemics, plague - caused by the bacterium Yersinia pestis is fatal in more than 30 percent of cases if left untreated, the study said.

As Africa's population soars, and food demand increases, scientists, farmers and politicians will have to balance the need for more farmland with concerns over the spread of disease, scientists said.

(Reporting By Chris Arsenault, editing by Ros Russell)

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