A sometimes lethal parasitic disease that can leave its victims with crater-like ulcers and grayish skin tones has never much bothered those within the confines of the U.S.— until now.

Between 2000 and 2007, 13 autochthonous cases— meaning victims contracted it here, as opposed to while traveling elsewhere— of leishmaniasis cropped up in Texas and Oklahoma, compared to just 29 cases spanning almost the entire 20th century, the American Journal of Tropical Medicine and Hygiene reported in 2012.

Why? The tropical disease is moving north, likely due to climate change, reports National Geographic. What's more, because leishmaniasis has heretofore been largely confined to impoverished realms, effective treatment isn't really available.

"It has not been a priority for drug development," says Dr. Peter Jay Hotez, dean of Baylor College of Medicine's National School of Tropical Medicine. Twenty-some people in a group of explorers "who plunged into nearly impenetrable Honduran rainforest in order to groundtruth the legend that it concealed a fabled 'white city'" contracted the parasitic disease, per National Geographic, thanks to the tiny sand fly, its vector.

And while these numbers may sound low—Outbreak News Today reports on "scores" of patients going to the hospital in Tripoli just last week—the Centers for Disease Control calculates that there are somewhere between 1 million and 2 million new cases a year throughout the world.

"In South Sudan, visceral leishmaniasis killed 10 times as many people as died in the Ebola outbreak of 2014-15—but it was silent, no one has covered this," says Hotez.

(Add leishmaniasis to the list of Syria's woes.)

This article originally appeared on Newser: This Disfiguring Disease Has Crossed the US Border

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