As a young child Emiliana Rodríguez recalls watching friends play a nighttime game of soccer, where one of the players suddenly dropped dead on the field. Not knowing what had happened, the Bolivian-born Rodríguez grew fearful of the night, afraid of the silent killer called Chagas, the “monster” she was told only comes out at night.

Chagas is a different kind of monster, a “silent and silenced disease,” transmitted by nocturnal bugs that infect up to 8 million people each year, and Rodríguez’ friend was one of 12,000 people killed each year.

Emiliana Rodríguez, 42, moved from Bolivia to Barcelona 27 years ago and realized she couldn’t escape Chagas, that she calls a “monster.”

“The fear usually came at night. Sometimes I didn’t sleep,” she said. “I was afraid of sleeping and not waking up.”