Characterizing Mesoamerican nephropathy (MeN), a devastating epidemic of chronic kidney disease (CKD) of unknown cause in Central America, has not been a straightforward endeavor. The first epidemiologic study reported that 67% of all new end-stage kidney disease cases in a referral hospital in El Salvador were not caused by traditional risk factors such as diabetes or hypertension. Further, and most importantly, the condition arose in a demographically unexpected group: young male farmers from coastal regions.