Climate change is warming the planet, and as a consequence, animals are moving to areas where they had never been detected before. Disease-carrying mosquitoes, including the minuscule sandflies, are expanding their geographical presence: leishmaniasis, a dangerous flesh-eating disease, is now moving to northern Texas.

Leishmaniasis affects 12 million people worldwide and kills about 70,000 people yearly, but receives no attention from drug companies because the protozoan thrives in the world's most impoverished areas. Available treatments are extremely toxic and can carry larger problems than the disease itself—they often lead to death. As of today, there is no guaranteed cure for this insidious disease.

In November 2016, while in Mexico, Agostino Petroni was bitten on the ear by a sandfly, which gave him leishmaniasis. The extremely toxic treatment lasted two years, but Petroni did not heal properly. Desperation brought Petroni to Mexico to meet Indigenous Mayan healers who cure the disease with local herbs and to Colombia for a consultation at a military hospital. Today, he is mostly OK, even if he has almost no ear left.

But many people are not as lucky: The disease is finding a new home in the United States, is conquering Morocco, and is spreading across the Mediterranean.