AbstractsMedical & Health Science

<italic>Background</italic> In spite of a large burden of diarrhea in children, surprisingly very little is known about the cause-composition of the main pathogenic agents of diarrhea. This uncertainty around the burden of diarrhea by etiology is problematic, especially in light of the pathogen-specific siloed interventions which are characteristic of current public health programs. It is thus critical to bridge this knowledge gap and identify the key pathogens, along with their distribution, that can cause diarrheal diseases in children in order to accurately assess health priorities. This study is the first to systematically review the literature on the cause composition of several pathogenic agents of diarrhea in children under 5 years of age. <italic>Methods and Findings</italic> We searched the literature for published studies on the proportion of diarrheal stools identified with pathogens from our comprehensive list of diarrheal etiologies. We used DisMod 3, a meta-regression tool, to estimate the proportion of diarrhea due to a given etiology for inpatient and outpatient cases of diarrheal disease in children under 5 in 2010. Of the 690,000 (95% UI: 520,000-820,000) deaths due to diarrheal diseases in children 2010, 18% (95% UI: 7.0%-36%) or 113,000 (95% UI: 44,000-228,000) deaths were caused by rotavirus. EPEC and ETEC comprised almost 13% of all deaths due to diarrhea in children, ranging from 11% of all diarrheal deaths in Sub-Saharan Africa, East and Sub-Saharan Africa, West to 18% in Central Europe. Other diarrheal diseases consistently represent the largest proportion of diarrheal deaths in children globally at 40% with 267,000 (95% UI: 109,000-515,000) deaths in 2010. We predicted 1.9 billion (95% UI: 937 million-3.3 billion) incident cases of diarrheal diseases in children in 2010. Cryptosporidiosis caused about 10%, or 208 million (95% UI: 89 million-410 million cases) of the global number of incident diarrheal cases. Rotavirus and EPEC caused 11% and 13% of incident diarrheal cases worldwide, respectively, with 229 million cases (95% UI: 123 million- 386 million cases) and 534 million cases (95% UI: 75million- 534 million cases). Other diarrheal diseases contributed the greatest proportion of all incident cases of diarrhea with 41% or 721 million cases (95% UI: 435million-1.1 billion cases). <italic>Conclusions</italic> The overwhelming proportion of both diarrhea mortality and morbidity caused by other diarrheal diseases highlights just how little is truly known about the etiology of diarrhea in children. Despite our best attempts to identify diarrheal pathogens that are most prevalent, we were still only able to attribute about 60% of all diarrheal deaths and cases in ages under 5 to specific pathogens. The uncertainty surrounding the pathogenic agents that cause the most cases and deaths due to diarrhea is significant. Not only are more studies on the burden of a wide array of diarrheal pathogens in all regions of the world desperately needed, but also better detection methods and surveillance of…