“[A] lack of any local epidemiological evidence about what actually causes diarrheal diseases and the impact they have on young children limit[s] the ability of public health officials, researchers, caretakers and parents to protect children from this devastating scourge,” Thomas Brewer, a deputy director on the Bill & Melinda Gates Foundation’s global health team who oversees the foundation’s work in enteric and diarrheal diseases, writes in the foundation’s “Impatient Optimists” blog. “Fortunately, we now have a better understanding thanks to the Global Enteric Multicenter Study (GEMS), which published data on the impact and leading causes of moderate-to-severe diarrhea in The Lancet last month,” he notes. He discusses some of the report’s findings, writing “just four pathogens — rotavirus, Cryptosporidium, Shigella and ST-ETEC — were responsible for the majority of diarrheal disease cases across all sites” in the study, and he examines “the impact [the data] can have in individual study countries.” He continues, “Regardless of context — whether in a country where the causes of diarrhea are a relative mystery or one in the final stages of developing its own rotavirus vaccine — fully understanding the problem is what enables us to act in the most effective way possible” (7/15).