Daily Climate: Seventeen years ago, Liliana Salvador Ibáñez’s year-old son came down with a high fever, then broke out with bleeding lesions on his legs. Four years later, his brother came down with the same illness, and a few years later a young niece died. All had bartonellosis, also known as Carrion’s disease, which is caused by a bacterium transmitted by a sand fly. In this Andean mountain valley in central Peru, mothers observed that there was an outbreak every four years or so. The cycle …