Malaria had nearly been eliminated around a giant dam in the Amazon — but then it came roaring back. Experts just discovered why.

Malaria had nearly been eliminated around a giant dam in the Amazon — but then it came roaring back. Experts just discovered why.

A years-long malaria control campaign in the Brazilian Amazon nearly eliminated the disease from a city — but then cases rebounded. Now, scientists think they've uncovered why.The campaign took place in northern Brazil during the construction of the Belo Monte Dam in the Xingu River, one of the largest hydroelectric dams in the world. From 2013 to 2017, the initiative slashed annual malaria rates from more than 1,200 cases to fewer than 60. But …