Kinetics of Enteric Pathogen Quantity During Acute Diarrhea in Children in Resource-Limited Settings

Pathogen quantity kinetics during childhood diarrhea have implications for etiology ascertainment. Using a multisite cohort, we modeled quantitative PCR quantity by symptom duration. Rotavirus had the largest log reduction in quantity by day 7 (−1.98; 95% confidence interval: −2.88, −1.08), followed by Shigella (−0.87; −1.46, −.28) and heat-stable toxin-producing Escherichia coli (−0.78; −1.57, .02). While peak quantity was robust to host factors, kinetics were not. For example, malnourished children had a minimal decline in Cryptosporidium quantity over the first 7 days of illness. Pathogen quantity, etiology attribution, and non-PCR test sensitivity all peaked early in illness. Diarrheal studies should collect samples early to reduce bias in etiology identification.